Intervenciones para prevenir la mastitis después del parto
Resumen
Antecedentes
A pesar de los efectos beneficiosos para la salud de la lactancia materna, las tasas de inicio y duración distan mucho de los valores de las guías internacionales. Muchos factores influyen en la decisión de una mujer de interrumpir la lactancia; la principal razón citada se asocia con complicaciones de la lactancia como la mastitis.
La mastitis es una inflamación de la mama, con o sin infección. La mastitis se puede ver como una secuencia patológica, desde una inflamación no infecciosa de la glándula mamaria hasta una infección que puede provocar la aparición de un absceso.
Objetivos
Evaluar la efectividad de las estrategias de prevención (por ejemplo, educación en lactancia materna, tratamientos farmacológicos y tratamientos alternativos) en la aparición o recurrencia de mastitis infecciosa o no infecciosa en madres que lactan después del parto.
Métodos de búsqueda
Se hicieron búsquedas en el registro de ensayos del Grupo Cochrane de Embarazo y Parto (Cochrane Pregnancy and Childbirth Group), ClinicalTrials.gov, en la plataforma de registros internacionales de ensayos clínicos de la OMS (ICTRP) (3 de octubre de 2019), y en las listas de referencias de los estudios obtenidos.
Criterios de selección
Se incluyeron ensayos controlados aleatorizados de intervenciones para la prevención de la mastitis en puérperas que lactan.
Fueron elegibles los ensayos controlados cuasialeatorizados y los ensayos comunicados solo en forma de resumen. Se intentó contactar con los autores para obtener cualquier resultado no publicado, siempre que fue posible.
Las intervenciones para prevenir la mastitis pueden incluir: probióticos, asesoramiento especializado sobre lactancia materna y enfoques holísticos.
Obtención y análisis de los datos
Dos autores de la revisión evaluaron de forma independiente los resultados de la búsqueda de los ensayos, extrajeron los datos y evaluaron el riesgo de sesgo y la certeza de la evidencia.
Resultados principales
Se incluyeron diez ensayos (3034 mujeres). Nueve ensayos (2395 mujeres) proporcionaron datos. Los ensayos tuvieron en general bajo riesgo de sesgo en la mayoría de los ámbitos, pero algunos tuvieron alto riesgo para el cegamiento, de sesgo de desgaste y de informe selectivo. En general el sesgo de selección (enmascaramiento de la asignación) fue incierto. La certeza de la evidencia se redujo debido al riesgo de sesgo y la imprecisión (escaso número de mujeres que participaron en los ensayos). Los conflictos de intereses de los autores de los ensayos y la participación de los patrocinadores de la industria también pueden haber repercutido en la certeza de la evidencia.
La mayoría de los ensayos informaron sobre le desenlace principal incidencia de mastitis, pero casi no hubo datos relacionados con los efectos adversos, el dolor de la mama, la duración de la lactancia, el daño del pezón, el absceso de la mama o la recurrencia de la mastitis.
Probióticos versus placebo
Los probióticos podrían reducir el riesgo de mastitis más que el placebo (riesgo relativo [RR] 0,51; intervalo de confianza [IC] del 95%: 0,35 a 0,75; dos ensayos; 399 mujeres; evidencia de certeza baja). No se conoce con certeza si los probióticos reducen el riesgo de dolor en los senos o de daño en los pezones porque la certeza de la evidencia es muy baja. Los resultados del mayor de estos ensayos (639 mujeres) no están disponibles actualmente debido a un acuerdo contractual entre el proveedor de los probióticos y los autores del ensayo. Los efectos adversos se informaron en un ensayo en el que ninguna mujer en ambos grupos experimentó efectos adversos.
Antibióticos versus placebo o atención habitual
El riesgo de mastitis podría ser similar entre los antibióticos y la atención habitual o placebo (RR 0,37; IC del 95%: 0,10 a 1,34; tres ensayos; 429 mujeres; evidencia de baja certeza). El riesgo de mastitis podría ser similar entre los antibióticos y el ungüento de ácido fusídico (RR 0,22; IC del 95%: 0,03 a 1,81; un ensayo; 36 mujeres; evidencia de certeza baja) o el ungüento de mupirocina (RR 0,44; IC del 95%: 0,05 a 3,89; un ensayo; 44 mujeres; evidencia de certeza baja), pero no se conoce con certeza debido a los IC amplios. Ninguno de los ensayos informó sobre efectos adversos.
Tratamientos tópicos versus asesoramiento sobre lactancia materna
El riesgo de mastitis podría ser similar entre el ungüento de ácido fusídico y el asesoramiento sobre lactancia materna (RR 0,77; IC del 95%: 0,27 a 2,22; un ensayo; 40 mujeres; evidencia de certeza baja) y el ungüento de mupirocina y el asesoramiento sobre lactancia materna (RR 0,39, IC del 95%: 0,12 a 1,35; un ensayo; 48 mujeres; evidencia de certeza baja), pero no se conoce con certeza debido a los IC amplios.
Un ensayo (42 mujeres) comparó los tratamientos tópicos entre sí. El riesgo de mastitis podría ser similar entre el ácido fusídico y la mupirocina (RR 0,51; IC del 95%: 0,13 a 2,00; evidencia de certeza baja), pero no existe seguridad debido a los IC amplios. No se informó de efectos adversos.
Educación especializada en lactancia materna versus atención habitual
El riesgo de mastitis (RR 0,93; IC del 95%: 0,17 a 4,95; un ensayo; 203 mujeres; evidencia de certeza baja) y el dolor de mama (RR 0,93; IC del 95%: 0,36 a 2,37; un ensayo; 203 mujeres; evidencia de certeza baja) podrían ser similares, pero no existe seguridad debido a los IC amplios. No se informó de efectos adversos.
Cereal que induce el factor antisecretor versus cereales estándar
El riesgo de mastitis (RR 0,24; IC del 95%: 0,03 a 1,72; un ensayo; 29 mujeres; evidencia de certeza baja) y la recurrencia de la mastitis (RR 0,39; IC del 95%: 0,03 a 4,57; un ensayo; siete mujeres; evidencia de certeza baja) podrían ser similares, pero no existe seguridad debido a los IC amplios. No se informó de efectos adversos.
Masaje en el punto de acupuntura versus atención habitual
El masaje en el punto de acupuntura probablemente reduce el riesgo de mastitis en comparación con la atención habitual (RR 0,38; IC del 95%: 0,19 a 0,78; un ensayo; 400 mujeres; evidencia de certeza moderada) y el dolor de mama (RR 0,13; IC del 95%: 0,07 a 0,23; un ensayo; 400 mujeres; evidencia de certeza moderada). No se informó de efectos adversos.
Masaje de la mama y electroterapia de baja frecuencia versus atención habitual
El masaje de mama y la electroterapia de baja frecuencia podrían reducir el riesgo de mastitis (RR 0,03; IC del 95%: 0,00 a 0,21; un ensayo; 300 mujeres; evidencia de certeza baja). No se informó de efectos adversos.
Conclusiones de los autores
Hay alguna evidencia de que el masaje en el punto de acupuntura es probablemente mejor que la atención habitual, los probióticos podrían ser mejores que placebo, y el masaje de la mama y la electroterapia de baja frecuencia podrían ser mejores que la atención habitual para prevenir la mastitis. Sin embargo, es importante señalar que se sabe de al menos un ensayo grande que investiga los probióticos y cuyos resultados no se han hecho públicos; por lo tanto, la evidencia presentada aquí no está completa.
La evidencia disponible con respecto a otras intervenciones, incluida la educación sobre la lactancia materna, los tratamientos farmacológicos y los tratamientos alternativos, indican que podrían ser un poco mejores que la atención habitual para prevenir la mastitis, pero estas conclusiones son poco claras a la baja certeza de la evidencia.
En los ensayos futuros se debería reclutar un número suficientemente grande de mujeres a fin de detectar diferencias clínicamente importantes entre las intervenciones, y los resultados de los ensayos futuros deberían ponerse a disposición del público.
PICO
Resumen en términos sencillos
Intervenciones para la prevención de la mastitis después del parto
Se planificó examinar la efectividad de las intervenciones utilizadas para evitar que las mujeres que lactan desarrollen una inflamación del tejido de la mama, conocida como mastitis.
¿Cuál es el tema?
La mastitis es una complicación frecuente de la lactancia. Provoca considerable dolor y sufrimiento a las mujeres y puede impedir que algunas madres den el pecho a sus recién nacidos durante el tiempo que deseen. Varios factores contribuyen al desarrollo de la mastitis, como la obstrucción de los conductos, el hecho de que las mamas estén demasiado llenas de leche, los pezones agrietados y que el recién nacido no pueda lactar correctamente. La mastitis puede ocurrir en uno o ambos senos y asociarse con varios síntomas que incluyen dolor de la mama, enrojecimiento e hinchazón, así como síntomas similares a la gripe. Los síntomas pueden durar desde dos a tres días, hasta un par de semanas o más.
¿Por qué es esto importante?
Es importante investigar los tratamientos para prevenir la mastitis a fin de maximizar los resultados y la duración de la lactancia. La lactancia materna tiene importantes efectos beneficiosos para la salud de los recién nacidos y sus madres, y las autoridades sanitarias y la Organización Mundial de la Salud recomiendan que los recién nacidos se alimenten exclusivamente de leche materna hasta los seis meses de edad. Se debe asegurar que las madres y los médicos y matronas que las atienden conozcan las mejores intervenciones para prevenir la mastitis, para ayudar a las mujeres a lactar con éxito durante todo el tiempo que quieran.
¿Qué evidencia se encontró?
Se buscó evidencia de ensayos controlados aleatorizados en octubre de 2019 y se identificaron diez ensayos (que incluyeron 3034 mujeres que lactaban). La mayoría de los ensayos informaron sobre el número de mujeres a las que se les diagnosticó mastitis, pero casi no hubo información sobre los efectos adversos, el dolor de la mama, la duración de la lactancia, el daño en los pezones, el absceso de la mama o la recurrencia de la mastitis. Ninguno de los ensayos fue patrocinado por la industria.
Tres ensayos (1038 mujeres) compararon los probióticos con placebo. Los resultados del mayor de estos ensayos (639 mujeres) no están disponibles actualmente debido a un acuerdo contractual entre el proveedor de probióticos y los autores del ensayo. Los probióticos podrían reducir el riesgo de mastitis en comparación con el placebo (evidencia de certeza baja). No se conoce con certeza si los probióticos reducen el riesgo de dolor en los senos o de daño en los pezones porque la certeza de la evidencia es muy baja.
El riesgo de mastitis podría ser similar entre los antibióticos y la atención habitual o el placebo (evidencia de certeza baja). El riesgo de mastitis podría ser similar entre los antibióticos y el ungüento de ácido fusídico, los antibióticos y el ungüento de mupirocina, el ungüento de ácido fusídico y el asesoramiento sobre lactancia materna, el ungüento de mupirocina y el asesoramiento sobre lactancia materna, el ácido fusídico y la mupirocina, una única sesión de educación especializada sobre lactancia materna y la atención habitual, el cereal que induce el factor antisecretor y el cereal estándar, pero no existe certeza acerca de estos resultados porque provienen de ensayos con un número reducido de participantes y la calidad de la evidencia es baja.
Es probable que el masaje en el punto de acupuntura reduzca el riesgo de mastitis y dolor de la mama en comparación con la atención habitual (evidencia de certeza moderada).
El masaje de mama y la electroterapia de baja frecuencia podrían reducir el riesgo de mastitis, en comparación con la atención habitual (evidencia de certeza baja).
¿Qué significa esto?
Es probable que el masaje en el punto de acupuntura ayude a prevenir la mastitis y el dolor en la mama, los probióticos podrían ser mejores que el placebo y el masaje de la mama y la electroterapia de baja frecuencia podrían ser mejores que la atención habitual. Sin embargo, en general no es posible asegurar cuáles son los tratamientos más efectivos para prevenir la mastitis porque la certeza de la evidencia es baja debido al riesgo de sesgo, el escaso número de mujeres que participan en los ensayos y las grandes diferencias entre los tratamientos, que hacen difícil hacer comparaciones significativas. Tampoco existe seguridad acerca de la verdadera efectividad de los probióticos porque se conoce al menos un ensayo de probióticos cuyos resultados no están disponibles públicamente.
Authors' conclusions
Summary of findings
| Probiotics compared to placebo for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with placebo | Risk with probiotics | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.51 | 399 | ⊕⊕⊝⊝ | ||
| 293 per 1000 | 149 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Study population | RR 0.33 (0.11 to 1.01) | 424 (1 RCT) | ⊕⊝⊝⊝ | ||
| 59 per 1000 | 19 per 1000 (6 to 59) | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Study population | RR 0.81 | 335 | ⊕⊕⊝⊝ | ||
| 522 per 1000 | 423 per 1000 | |||||
| Number of women with adverse events | In one trial no women in either the probiotics group or the placebo group experienced adverse events | 108 | ⊕⊕⊝⊝ | |||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to risk of bias: unclear allocation concealment, high risk of reporting bias, and missing data 2 Downgraded one level for indirectness: measured as number of women using topical treatment for nipple cracks 3 Downgraded one level due to risk of bias: unclear allocation concealment and high risk of selective reporting 4 Downgraded one level for imprecision: 95% confidence interval is consistent with possible benefit and possible harm 5 Downgraded two levels for imprecision: few participants and no events | ||||||
| Antibiotics compared to usual care or placebo for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with usual care or placebo | Risk with antibiotics | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.37 | 429 | ⊕⊕⊝⊝ | ||
| 37 per 1000 | 14 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse effects | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to imprecision: low event rate and wide 95% CIs indicating the true effect may be either appreciable benefit or harm | ||||||
| Antibiotics compared to topical treatments for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with topical treatments | Risk with antibiotics | |||||
| Incidence of mastitis within 6 months postpartum ‐ Antibiotics versus fusidic acid ointment | Study population | RR 0.22 | 36 | ⊕⊕⊝⊝ | ||
| 235 per 1000 | 52 per 1000 | |||||
| Incidence of mastitis within 6 months postpartum ‐ Antibiotics versus mupirocin ointment | Study population | RR 0.44 | 44 | ⊕⊕⊝⊝ | ||
| 120 per 1000 | 53 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse effects | Not reported | |||||
| 1 Downgraded two levels due to imprecision: single small trial with wide 95% CIs, indicating that the true effect may be either appreciable benefit or harm | ||||||
| Topical treatments compared to breastfeeding advice for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with breastfeeding advice | Risk with topical treatments | |||||
| Incidence of mastitis within 6 months postpartum ‐ Fusidic acid ointment versus breastfeeding advice | Study population | RR 0.77 | 40 | ⊕⊕⊝⊝ | ||
| 304 per 1000 | 234 per 1000 | |||||
| Incidence of mastitis within 6 months postpartum ‐ Mupirocin ointment versus breastfeeding advice | Study population | RR 0.39 | 48 | ⊕⊕⊝⊝ | ||
| 304 per 1000 | 119 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to imprecision: single small trial with wide 95% CIs, indicating that the true effect may be either appreciable benefit or harm | ||||||
| Mupirocin ointment compared to fusidic acid ointment for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with fusidic acid ointment | Risk with Mupirocin ointment | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.51 | 42 | ⊕⊕⊝⊝ | ||
| 235 per 1000 | 120 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to imprecision: single small trial with wide 95% CIs, indicating that the true effect may be either appreciable benefit or harm | ||||||
| Specialist breastfeeding education compared to usual care for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with usual care | Risk with specialist breastfeeding education | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.93 | 203 | ⊕⊕⊝⊝ | This outcome was measured at 30 days postpartum | |
| 30 per 1000 | 28 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain (sore nipples) | Study population | RR 0.93 | 203 | ⊕⊕⊝⊝ | ||
| 91 per 1000 | 85 per 1000 | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to imprecision: single small trial with wide 95% CIs, indicating that the true effect may be either appreciable benefit or harm | ||||||
| Anti‐secretory factor‐inducing cereal compared to standard cereal for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with standard cereal | Risk with anti‐secretory factor‐inducing cereal | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.24 | 29 | ⊕⊕⊝⊝ | ||
| 353 per 1000 | 85 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Study population | RR 0.39 | 7 | ⊕⊕⊝⊝ | ||
| 667 per 1000 | 260 per 1000 | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels for imprecision: few participants and wide 95% CIs indicating the true effect may be either appreciable benefit or harm | ||||||
| Acupoint massage compared to routine care for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women Setting: obstetric outpatient clinic | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with routine care | Risk with acupoint massage | |||||
| Incidence of mastitis within 6 months postpartum) | Study population | RR 0.38 | 400 | ⊕⊕⊕⊝ | ||
| 130 per 1000 | 49 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Study population | RR 0.13 | 400 | ⊕⊕⊕⊝ | ||
| 400 per 1000 | 52 per 1000 | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded one level due to unclear risk of bias across most domains | ||||||
| Breast message and low frequency pulse treatment compared to routine care for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with routine care | Risk with breast message and low frequency pulse treatment | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.03 | 300 | ⊕⊕⊝⊝ | ||
| 233 per 1000 | 7 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported for either the duration of exclusive or any breastfeeding | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded one level due to unclear risk of selection, performance and detection bias 2 Downgraded one level for imprecision: few events | ||||||
Background
The World Health Organization (WHO) recognises the short‐ and long‐term benefits of breastfeeding and recommends exclusive breastfeeding until six months of age (Kramer 2002; Kramer 2012; World Health Organization 2008). The epidemiologic evidence overwhelmingly supports breastfeeding as being protective of infant, maternal, family and community health (Kramer 2002; Kramer 2012; World Health Organization 2008). The improved nutrition, immunological, psychological, economical and environmental benefits that breastfeeding provides are well documented (Anatolitou 2012; Chezem 2003). Specifically, breast milk protects infants and children against conditions such as gastroenteritis and respiratory infections (Anatolitou 2012; MacDonald 2003); moreover babies who are not breastfed are predisposed to many health complications in later life, including high blood pressure, obesity, non‐insulin dependent diabetes and ischaemic heart disease (Thompson 2005). The short‐ and long‐term benefits of breastfeeding to the mother include the increase of uterine contractions post‐delivery, resulting in a reduction of postpartum bleeding (Chua 1994; Anatolitou 2012). Breastfeeding also enhances a faster return to the pre‐pregnant body weight (Anatolitou 2012; Dewey 1999), as well as possible protection against osteoporosis, ovarian and uterine cancer (Anatolitou 2012; Cummings 1993; Melton 1993; Rosenblatt 1993; Siskind 1997).
Despite the recognised health, emotional, psychosocial and societal benefits of breastfeeding to women and children, breastfeeding rates worldwide are suboptimal, especially among low‐income women. Increasing breastfeeding initiation and duration amongst low‐income women would not only offer improved health benefits to both the mother and infant, but would lessen the economic burden experienced by this group of people within the community (Anatolitou 2012; Guttman 2000; Mitra 2004).
Description of the condition
There are many factors that may influence a woman's decision to cease breastfeeding. However, the main reason cited for stopping breastfeeding is related to complications of lactation (Boakes 2018; Dener 2003). Mastitis is a significant complication and is a common problem in lactating women (Boakes 2018; Dener 2003). This debilitating condition may contribute to weaning in the first three weeks (Boakes 2018; Schwartz 2002) and has been reported as the third most common reason for weaning (Fetherston 1997), with one in four breastfeeding women citing mastitis as the reason they weaned (Michie 2003). However, the incidence of mastitis has been reported to be as high as 33% in breastfeeding women (Jahanfar 2013). Mastitis may also contribute to some women experiencing negative emotions, including distress, depression and anxiety as well as a feeling of helplessness (Amir 2006).
The definition of mastitis varies throughout the literature; WHO defines mastitis as "an inflammatory condition of the breast, which may or may not be accompanied by infection" (Amir 2007; Fetherston 1998; World Health Organization 2008). Non‐infective mastitis may result from milk stasis, blocked ducts, engorgement or physical injury to the breast. Infective mastitis may result from cracked or traumatised nipples; interruption in the nipples' integrity provides a route for micro‐organisms to enter the breast (Fetherston 1998). Mastitis can be viewed as a continuum of disease, from non‐infective inflammation of the breast to infection that may lead to abscess formation. Mastitis presents with a plethora of clinical symptoms; it can present unilaterally or bilaterally with breast pain, redness and swelling; and may be associated with flu‐like symptoms (Amir 2007; Jahanfar 2013). The type of mastitis experienced may affect the duration of symptoms, from two to three days to as long as 14 days or more (Thomsen 1984). The prevalence of mastitis varies depending on the definition and the number of weeks postpartum (Kinlay 2001; Potter 2005; Semba 2000). Studies following participants from three to 12 months have reported incidence rates of mastitis of 23.7% to 27.1% (Fetherston 1998; Vogel 1999), while the recurrence of mastitis is between 6.5% and 8.5% (Fetherston 1997; Vogel 1999). However, Boakes conducted a study in 2018 that reported the global prevalence of mastitis ranging from between 1% to 10% in lactating woman (Boakes 2018.
Description of the intervention
Health education and peer support have been identified as interventions that improve the initiation of breastfeeding amongst low‐income populations where breastfeeding initiation rates are typically low (Dyson 2005). However, antenatal breastfeeding education has been explored as an intervention to improve breastfeeding duration rates (Anatolitou 2012; Lumbiganon 2016). The literature also suggests that education and support, along with correct breastfeeding practices such as good positioning and the correct attachment of the baby to the breast, lead to improved breastfeeding exclusivity and duration (Anatolitou 2012; Fetherston 1998; Inch 2006; Potter 2005) and one study has postulated that breastfeeding education may positively impact on the prevention of mastitis (Flores 2002). Breastfeeding education can take many forms, such as in group and/or one‐to‐one sessions, informative literature and telephone and/or online support.
Poor breast attachment and inadequate breast drainage when feeding are issues that have been linked to women developing mastitis (Amir 2014; Bell 1998; Inch 2006). Breastfeeding frequently, alternating the breast that feeds are started from, and the position used to feed the infant, may all help to relieve engorgement. Breast compression or breast massage before latching is an effective way to avoid blocked ducts that may lead to mastitis. Frequent feeding and the use of electric or hand pumps may assist by efficiently emptying the breast, and reduce breast engorgement and milk stasis. Previous work has suggested that if left untreated, these conditions may develop into mastitis (Amir 2014; Foxman 2002). Avoiding the use of ill‐fitting clothes or bras and sleeping on the stomach are among other measures that women can take to reduce pressure on breast tissue. Such pressure can lead to blocked milk ducts or traumatised breast tissue, which is another precursor to mastitis. Taking care of oneself, getting plenty of rest, adequate fluids and a nutritious diet are all seen as preventive treatments to help manage maternal stress and fatigue, which are factors seen to precede mastitis (Spowart 2004; Wambach 2016). Studies by Roberts 1998 have shown that cabbage leaves can be used to help manage engorgement by reducing pain and discomfort. Antibiotics have also been used as a preventive treatment for women that are predisposed to recurrent mastitis (Cusack 2011; Fetherston 1998; Foxman 1994; Jahanfar 2013). However, there is insufficient evidence to confidently conclude that antibiotics therapy is effective in the management of mastitis (Jahanfar 2013).
Other interventions that have been trialed as interventions in the treatment of mastitis are topical ointments to treat painful, infected nipples with a view to preventing the further onset of mastitis (Livingstone 1999), hydrothermically processed cereal with anti‐secretory factor‐inducing properties (Svensson 2004), and acupoint massage (He 2015).
How the intervention might work
Interventions intended to prevent mastitis might work in several ways. Some interventions aim to facilitate milk extraction from the breast, some focus on breastfeeding knowledge and technique, while others are thought to have anti‐inflammatory and anti‐infection effects. The interventions investigated here are underpinned by a range of assumptions:
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breastfeeding education; to improve women's understanding of breastfeeding physiology and management, including relaxation, stress and fatigue management, and correct positioning of baby at the breast, thought to reduce the risk of nipple damage as well as facilitate adequate drainage of milk from the breast. Evidence from randomised controlled trials and observational studies shows that counselling and educational interventions delivered at home and in the community help to improve breastfeeding rates (Sinha 2015), therefore, it is possible that these types of interventions could also help to reduce mastitis rates.
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acupoint massage and/or breast massage before and during breastfeeding; to facilitate milk extraction from the breast, and to soften breast tissue when draining the breast of milk. A systematic review indicates that massage interventions can help to reduce pain in women with a range of breastfeeding problems (Anderson 2019). Observational study evidence suggests that therapeutic massage can help relieve symptoms in women with engorgement, plugged ducts or mastitis (Witt 2016).
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administration of topical treatments to painful, infected nipples with the intention of preventing further infection and the onset of mastitis. Purified lanolin may be beneficial in the treatment of sore nipples.The management of sore nipples may reduce the risk of developing mastitis in some women (Spencer 2008).
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use of probiotics, whose anti‐inflammatory effects may prevent mastitis. It is thought that supplements containing specific strains of Lactobacilli from human milk may have a protective effect against breast infection in breastfeeding women since the micro‐organisms in the probiotics can travel from the gastrointestinal tract to the mammary glands (Amir 2016). There have been few studies published regarding probiotics in the treatment or prevention of mastitis, and with mixed results, however, healthcare professionals in some parts of the world are already receiving direct marketing of probiotic products despite the paucity of evidence for their effectiveness (Amir 2016).
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hydrothermically processed nutritional interventions designed to induce anti‐secretory factor (AF) in human milk, thought to reduce the risk of infection. AF helps to prevent diarrhoea and inflammation of the intestines (Lange 2001) and it is thought that there may be an association between high levels of active AF in plasma and breast milk, and a reduced risk of infection (Gustafsson 2018).
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use of prophylactic antibiotics; to prevent the onset of infection and to manage recurrence of mastitis. The use of antibiotics in the early presentation of mastitis is a considered management treatment (Auckland District Health Board 2017) and it is possible that antibiotics could be used as a preventive measure to avoid developing advanced presentation of mastitis.
Why it is important to do this review
Currently, a variety of interventions are used in clinical practice for the prevention of mastitis following childbirth. Uncertainties remain about their effectiveness and their possible impact on breastfeeding. It is important to identify, synthesise and assess the certainty of the existing evidence relating to the effectiveness and safety of interventions to prevent mastitis in order to enable women and clinical decision makers to make better informed decisions. Additionally, new randomised studies have been conducted since the previous version of this review was published in 2012 which need to be incorporated to ensure our findings are up‐to‐date and to help inform international clinical guidelines.
Objectives
To assess the effectiveness of preventive strategies (for example, breastfeeding education, pharmacological treatments and alternative therapies) on the occurrence or recurrence of non‐infective or infective mastitis in breastfeeding women post‐childbirth.
Methods
Criteria for considering studies for this review
Types of studies
Eligible studies were randomised controlled trials (RCTs), quasi‐RCTs and cluster‐randomised trials with the purpose of evaluating one or more interventions to prevent mastitis. Trials reported only in abstract form were also eligible for inclusion.
Types of participants
Postpartum women, either primiparous or multiparous, who are breastfeeding or who intend to breastfeed both exclusively and partially. We included studies where some of the women had had mastitis previously or who had symptoms, such as cracked nipples, but all the studies were in women who did not currently have mastitis.
Types of interventions
Any intervention intended to prevent mastitis versus any other intervention intended to prevent mastitis or versus no intervention (placebo), administered towards the end of pregnancy or in the first few weeks postpartum.
Types of interventions may include:
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breastfeeding education, information, and support (including relaxation, stress and fatigue management, correct positioning of baby at the breast);
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acupoint and breast massage before and during breastfeeding;
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prophylactic antibiotics;
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probiotics;
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topical ointments;
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anti‐secretory factor‐inducing nutritional interventions.
Types of outcome measures
The following primary and secondary outcomes were selected through discussion amongst the author team.
Primary outcomes
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Incidence of mastitis within six months postpartum, diagnosed by a combination of women's self‐reported symptoms and clinical examination
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Recurrence of mastitis within 12 months postpartum
Secondary outcomes
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Breast abscess within six months postpartum
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Nipple damage within six months postpartum
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Duration of exclusive breastfeeding (where the baby receives no other food or drink, not even water)
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Duration of any breastfeeding (where the baby receives breastmilk in addition to any other nutrition)
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Breast pain
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Breast engorgement
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Women's perception of milk supply
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Maternal breastfeeding satisfaction (measured by Maternal Breastfeeding Evaluation Scale (Leff 1994))
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Maternal breastfeeding confidence (measured by Breastfeeding Self‐efficacy Scale (Dennis 1999))
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Cessation of breastfeeding within six months postpartum
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Number of women with adverse events
Search methods for identification of studies
The following methods section is based on a standard template used by Cochrane Pregnancy and Childbirth.
Electronic searches
For this update, we searched Cochrane Pregnancy and Childbirth’s Trials Register by contacting their Information Specialist (3 October 2019).
The Register is a database containing over 26,000 reports of controlled trials in the field of pregnancy and childbirth. It represents over 30 years of searching. For full current search methods used to populate Pregnancy and Childbirth’s Trials Register including the detailed search strategies for CENTRAL, MEDLINE, Embase and CINAHL; the list of handsearched journals and conference proceedings; and the list of journals reviewed via the current awareness service; please follow this link.
Briefly, Cochrane Pregnancy and Childbirth’s Trials Register is maintained by their Information Specialist and contains trials identified from:
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monthly searches of the Cochrane Central Register of Controlled Trials (CENTRAL);
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weekly searches of MEDLINE (Ovid);
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weekly searches of Embase (Ovid);
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monthly searches of CINAHL (EBSCO);
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handsearches of 30 journals and the proceedings of major conferences;
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weekly current awareness alerts for a further 44 journals plus monthly BioMed Central email alerts.
Search results are screened by two people and the full text of all relevant trial reports identified through the searching activities described above is reviewed. Based on the intervention described, each trial report is assigned a number that corresponds to a specific Pregnancy and Childbirth review topic (or topics), and is then added to the Register. The Information Specialist searches the Register for each review using this topic number rather than keywords. This results in a more specific search set that has been fully accounted for in the relevant review sections (Included studies; Excluded studies; Ongoing studies).
In addition, we searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) for unpublished, planned and ongoing trial reports (3 October 2019) using the search methods detailed in Appendix 1.
Searching other resources
We searched the reference lists of retrieved studies.
We did not apply any language or date restrictions.
(For details of the search methods used in the previous review, please see Crepinsek 2012.)
Data collection and analysis
For methods used in the previous version of this review, seeCrepinsek 2012.
For this update, the following methods (based on a standard group template) were used for assessing the reports that were identified as a result of the updated search.
Selection of studies
Two review authors (ET and FS) independently assessed for inclusion all the potential studies identified as a result of the search strategy. We resolved any disagreement through discussion or, if required, we consulted a third review author.
Data extraction and management
We designed a form to extract data. For eligible studies, two review authors (ET and FS) extracted the data using the agreed form. We resolved discrepancies through discussion or, if required, we consulted a third review author (MC). Data were entered into Review Manager software (RevMan 2014) and checked for accuracy.
When information regarding any of the above was unclear, we contacted authors of the original reports to request further details.
Assessment of risk of bias in included studies
Two review authors (ET and FS) independently assessed risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2019). Any disagreement was resolved by discussion or by involving a third assessor.
(1) Random sequence generation (checking for possible selection bias)
We described for each included study the method used to generate the allocation sequence in sufficient detail to allow an assessment of whether it should produce comparable groups.
We assessed the method as:
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low risk of bias (any truly random process, e.g. random number table; computer random number generator);
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high risk of bias (any non‐random process, e.g. odd or even date of birth; hospital or clinic record number);
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unclear risk of bias.
(2) Allocation concealment (checking for possible selection bias)
We described for each included study the method used to conceal allocation to interventions prior to assignment and assessed whether intervention allocation could have been foreseen in advance of, or during recruitment, or changed after assignment.
We assessed the methods as:
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low risk of bias (e.g. telephone or central randomisation; consecutively numbered sealed opaque envelopes);
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high risk of bias (open random allocation; unsealed or non‐opaque envelopes, alternation; date of birth);
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unclear risk of bias.
(3.1) Blinding of participants and personnel (checking for possible performance bias)
We described for each included study the methods used, if any, to blind study participants and personnel from knowledge of which intervention a participant received. We considered that studies were at low risk of bias if they were blinded, or if we judged that the lack of blinding was unlikely to affect results. We assessed blinding separately for different outcomes or classes of outcomes.
We assessed the methods as:
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low, high or unclear risk of bias for participants;
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low, high or unclear risk of bias for personnel.
(3.2) Blinding of outcome assessment (checking for possible detection bias)
We described for each included study the methods used, if any, to blind outcome assessors from knowledge of which intervention a participant received. We assessed blinding separately for different outcomes or classes of outcomes.
We assessed methods used to blind outcome assessment as:
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low, high or unclear risk of bias.
(4) Incomplete outcome data (checking for possible attrition bias due to the amount, nature and handling of incomplete outcome data)
We described for each included study, and for each outcome or class of outcomes, the completeness of data including attrition and exclusions from the analysis. We stated whether attrition and exclusions were reported and the numbers included in the analysis at each stage (compared with the total randomised participants), reasons for attrition or exclusion where reported, and whether missing data were balanced across groups or were related to outcomes. Where sufficient information was reported, or could be supplied by the trial authors, we planned to re‐include missing data in the analyses which we undertook.
We assessed methods as:
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low risk of bias (e.g. no missing outcome data; missing outcome data balanced across groups);
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high risk of bias (e.g. numbers or reasons for missing data imbalanced across groups; ‘as treated’ analysis done with substantial departure of intervention received from that assigned at randomisation);
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unclear risk of bias.
(5) Selective reporting (checking for reporting bias)
We described for each included study how we investigated the possibility of selective outcome reporting bias and what we found.
We assessed the methods as:
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low risk of bias (where it is clear that all of the study’s prespecified outcomes and all expected outcomes of interest to the review have been reported);
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high risk of bias (where not all the study’s prespecified outcomes have been reported; one or more reported primary outcomes were not prespecified; outcomes of interest are reported incompletely and so cannot be used; study fails to include results of a key outcome that would have been expected to have been reported);
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unclear risk of bias.
(6) Other bias (checking for bias due to problems not covered by (1) to (5) above)
We described for each included study any important concerns we had about other possible sources of bias.
(7) Overall risk of bias
We made explicit judgements about whether studies were at high risk of bias, according to the criteria given in the Handbook (Higgins 2019). With reference to (1) to (6) above, we planned to assess the likely magnitude and direction of the bias and whether we considered it was likely to impact on the findings. In future updates, we will explore the impact of the level of bias through undertaking sensitivity analyses ‐ seeSensitivity analysis.
Measures of treatment effect
Dichotomous data
For dichotomous data, we presented results as summary risk ratio with 95% confidence intervals.
Continuous data
We used the mean difference if outcomes were measured in the same way between trials. We used the standardised mean difference to combine trials that measured the same outcome, but used different methods.
Time‐to‐event data
We did not identify any data relating to duration of breastfeeding. In future updates, where data are available we will use time‐to‐event analysis and present hazard ratios and 95% confidence intervals.
Unit of analysis issues
Cluster‐randomised trials
No cluster‐randomised trials were identified. In future updates of the review, we will include cluster‐randomised trials in the analyses along with individually randomised trials. We will adjust their sample sizes using the methods described in section 23.1.4 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2019) using an estimate of the intracluster correlation co‐efficient (ICC) derived from the trial (if possible), from a similar trial or from a study of a similar population. If we use ICCs from other sources, we will report this and conduct sensitivity analyses to investigate the effect of variation in the ICC. If we identify both cluster‐randomised trials and individually‐randomised trials, we plan to synthesise the relevant information. We will consider it reasonable to combine the results from both if there is little heterogeneity between the study designs and the interaction between the effect of intervention and the choice of randomisation unit is considered to be unlikely.
We will also acknowledge heterogeneity in the randomisation unit and perform a sensitivity analysis to investigate the effects of the randomisation unit.
Cross‐over trials
Cross‐over trials would not be a suitable design for this intervention, therefore, were not eligible for inclusion.
Other unit of analysis issues
The unit of analysis is each woman who is randomised to a treatment group. We analysed trials with more than two arms by treating each pair of arms as a separate comparison.
Dealing with missing data
For included studies, levels of attrition were noted. In future updates, if more eligible studies are included, the impact of including studies with high levels of missing data in the overall assessment of treatment effect will be explored by using sensitivity analysis.
For all outcomes, analyses were carried out, as far as possible, on an intention‐to‐treat basis, i.e. we attempted to include all participants randomised to each group in the analyses. The denominator for each outcome in each trial was the number randomised minus any participants whose outcomes were known to be missing.
Assessment of heterogeneity
We assessed statistical heterogeneity in each meta‐analysis through visual inspection of forest plots and consideration of the I2 statistic.
As strict thresholds for interpretation of I2 are not recommended, we used the guide to interpretation in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2019).
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0% to 40%: might not be important
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30% to 60%: may represent moderate heterogeneity
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50% to 90%: may represent substantial heterogeneity
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75% to 100%: considerable heterogeneity
When I² lay in an area of overlap between two categories (e.g. between 50% and 60%), we considered differences in participants and interventions among the trials contributing data to the analysis (Higgins 2019).
Assessment of reporting biases
In future updates, if there are 10 or more studies in the meta‐analysis, we will investigate reporting biases (such as publication bias) using funnel plots. We will assess funnel plot asymmetry visually. If asymmetry is suggested by a visual assessment, we will perform exploratory analyses to investigate it.
Data synthesis
We carried out statistical analysis using the Review Manager software (RevMan 2014). We used fixed‐effect meta‐analysis for combining data where it was reasonable to assume that studies were estimating the same underlying treatment effect: i.e. where trials were examining the same intervention, and the trials’ populations and methods were judged sufficiently similar.
In future updates, if there is clinical heterogeneity sufficient to expect that the underlying treatment effects differed between trials, or if substantial statistical heterogeneity is detected, we will use random‐effects meta‐analysis to produce an overall summary if an average treatment effect across trials is considered clinically meaningful. The random‐effects summary is treated as the average of the range of possible treatment effects and we will discuss the clinical implications of treatment effects differing between trials. If the average treatment effect is not clinically meaningful, we will not combine trials. If we use random‐effects analyses, the results will be presented as the average treatment effect with 95% confidence intervals, and the estimates of Tau² and I².
Subgroup analysis and investigation of heterogeneity
We did not identify substantial heterogeneity. In future updates, we will investigate heterogeneity using subgroup analyses and sensitivity analyses.
In future updates, we will carry out subgroup analysis to investigate if interventions have different effects in women who have previously experienced mastitis after childbirth compared to women who have never had mastitis. We will limit subgroup analysis to the two primary outcomes of incidence of mastitis and recurrence of mastitis.
We will assess subgroup differences in future reviews by interaction tests available within RevMan (RevMan 2014) and we will report the results of subgroup analyses quoting the Chi² statistic and P value, and the interaction test I² value.
Sensitivity analysis
We did not identify sufficient numbers of trials to undertake sensitivity analysis but in future updates we plan to carry out sensitivity analyses to explore the effect of risk of bias by excluding trials at high risk of bias from the analysis.
Summary of findings and assessment of the certainty of the evidence
The certainty of the evidence was assessed using the GRADE approach as outlined in the GRADE handbook in order to assess the certainty of the body of evidence relating to the following outcomes.
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Incidence of mastitis within six months postpartum.
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Recurrence of mastitis within 12 months postpartum.
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Breast abscess within six months postpartum.
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Nipple damage within six months postpartum.
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Duration of any breastfeeding.
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Breast pain.
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Number of women with adverse events.
The GRADEpro Guideline Development Tool was used to import data from Review Manager 5.3 (RevMan 2014) in order to create ’Summary of findings’ tables. A summary of the intervention effect and a measure of certainty for each of the above outcomes were produced using the GRADE approach. The GRADE approach uses five considerations (study limitations, consistency of effect, imprecision, indirectness and publication bias) to assess the certainty of the body of evidence for each outcome. The evidence can be downgraded from 'high certainty' by one level for serious (or by two levels for very serious) limitations, depending on assessments for risk of bias, indirectness of evidence, serious inconsistency, imprecision of effect estimates or potential publication bias.
Results
Description of studies
Results of the search
We retrieved 23 trial reports from the updated search and also reassessed (Gensch 2006) which was awaiting classification in the previous version of the review. This trial did not meet the inclusion criteria and was excluded. There are two ongoing studies that will be reviewed at a later date. Five new trials were identified that met the inclusion criteria, giving a total of 10 trials in the review (Figure 1).
Study flow diagram.
Included studies
We identified 10 trials (3034 women) that met the inclusion criteria (see Characteristics of included studies). The trials were conducted between 1999 and 2018.
Design
All of the included studies were randomised controlled trials (RCTs). One trial had four arms (Livingstone 1999) and the others were all two‐arm trials.
Setting
All of the studies were conducted in middle or high‐income countries. Two trials were conducted in each of the following countries, Australia (Amir 2004; Bond 2018), Spain (Fernandez 2016; Hurtado 2017) and China (Fang 2016; He 2015). The further studies were conducted in Brazil (De Oliveira 2006), Canada (Livingstone 1999), South Africa (Sebitloane 2008) and Sweden (Svensson 2004).
Sample size
The sample size ranged from 10 women (Amir 2004) to 639 women (Bond 2018). The mean number of women randomised in each trial was 304.
Population
The participants in the trials were women with uncomplicated pregnancies and healthy, full‐term infants.
Six trials recruited women who were asymptomatic (Bond 2018; De Oliveira 2006; He 2015; Hurtado 2017; Sebitloane 2008; Svensson 2004)
In two trials, all the women had sore or cracked nipples (Amir 2004; Livingstone 1999). In one trial, all the women had low milk supply (Fang 2016) and in another all the women had a history of mastitis in previous pregnancies (Fernandez 2016).
Interventions
One trial delivered its intervention before the women gave birth (Fernandez 2016). In one trial, the intervention was delivered while the women were in active labour (Sebitloane 2008). In five trials, the interventions began in the immediate postpartum period: before discharge from hospital (De Oliveira 2006; Fang 2016; He 2015); or during the first week postpartum (Hurtado 2017; Svensson 2004). Three trials did not state how long after giving birth they began their interventions (Amir 2004; Bond 2018; Livingstone 1999).
Of the 10 trials that met the pre‐stated inclusion criteria in this review, three trials compared probiotics to placebo (Bond 2018; Fernandez 2016; Hurtado 2017). One trial evaluated breastfeeding education (De Oliveira 2006). One trial compared basic breastfeeding advice in combination with topical treatments ‐ this trial also included an antibiotic arm to the trial (Livingstone 1999). The four arms of the Livingstone 1999 trial were: optimal breastfeeding advice (n = 23); topical 2% mupirocin ointment applied to the nipples (n = 25); topical fusidic acid ointment applied to the nipples (n = 17); and oral antibiotics ‐ cloxacillin/erythromycin (n = 19).
One trial evaluated hydrothermally processed cereals with anti‐secretory factor‐inducing properties. Anti‐secretory factor is a protein found in most human tissue including the placenta and possibly occurring in milk, which has been shown to have possible anti‐infectious and anti‐inflammatory capabilities (Svensson 2004).
Two other trials investigated the use of antibiotics (Amir 2004; Sebitloane 2008). The trial by He 2015 investigated the effects of breast acupoint massage with early breastfeeding and breastfeeding education, while the trial by Fang 2016 investigated breast massage combined with low frequency pulse treatment.
Outcomes
All 10 trials measured the primary outcome, incidence of mastitis, with one trial also reporting mastitis recurrence.
One study reported sore nipples (De Oliveira 2006) and two studies reported breast engorgement (De Oliveira 2006; He 2015).
Breastfeeding outcomes were addressed in two trials. Exclusive breastfeeding was reported in two trials (Fang 2016; He 2015) and any breastfeeding, breastfeeding problems or perceived low milk supply were each addressed in a single trial (Fang 2016).
The mastitis study by Amir 2004 was aborted at 12 months due to poor intervention compliance and lack of eligible participants. The study by Bond 2018 measured the incidence of mastitis up to eight weeks following birth. However, no data were available due to restrictions placed on the authors by the probiotics providers.
De Oliveira 2006 reported the measures of exclusive breastfeeding rates and breastfeeding‐related problems. They also reported the measures of mastitis, sore nipples and engorgement. The study by Fang 2016 reported a hypogalactia degree score, postpartum lactation initiating, milk volume effect and mastitis morbidity. Fernandez 2016 reported the occurrence of mastitis during the first three months after delivery. They also collected data on breast pain from women who had mastitis. Adverse events and side effects related to the ingestion of the probiotic were also reported. He 2015 reported the Initial time of lactation and the amount of lactation, breastfeeding rate after 42 days, breast comfort, swelling, incidence of mastitis after 42 days, and nursing satisfaction.
Hurtado 2017 reported the incidence of clinical mastitis during the first four months of breastfeeding. Mastitis was defined as at least two out of the three breast symptoms (pain, redness, and lump) and at least one of fever or flu‐like symptoms (shivering, hot sweats, or aches). Secondary outcomes ‐ the microbiota of breast milk at the end of the intervention and in mastitis events, monthly questionnaire on evaluation of breast pain, and inflammatory markers in breast milk at the end of intervention and in mastitis events ‐ were also measured.
Livingstone 1999 measured nipple symptoms, breast symptoms and mastitis, while Sebitloane 2008 reported postpartum infections and Svensson 2004 reported the incidence of mastitis.
Sources of funding
Nine trials received state and/or academic institution funding (Amir 2004; Bond 2018; Fang 2016; Fernandez 2016; He 2015; Hurtado 2017; Livingstone 1999; Sebitloane 2008; Svensson 2004).
One trial also received funding from intervention manufacturers (Amir 2004).
One trial did not mention any sources of funding (De Oliveira 2006).
Declarations of interest
One trial declared that the authors had no conflicts of interest but that the intervention and comparator were donated by a private company, which would have no direct influence on the conduct, design or implementation of the trial and that there were no commercial benefits for the trials authors (Bond 2018).
One trial made a declaration of interest because several of its authors were employees of the manufacturer of the probiotic intervention (Hurtado 2017).
Three trials reported that the authors had no conflicts of interest or declarations of interest to declare (Amir 2004; De Oliveira 2006; Fernandez 2016).
Five trials did not mention declarations of interest (Fang 2016; He 2015; Livingstone 1999; Sebitloane 2008; Svensson 2004).
Excluded studies
SeeCharacteristics of excluded studies.
We excluded 41 studies, mostly because the trials in question were not aimed at preventing mastitis, or were not RCTs. Trials were also excluded it they were reporting the treatment of mastitis rather than the prevention of mastitis.
Studies were excluded from the review for the following reasons:
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Seven studies were not randomised trials (Blaikeley 1953; Evans 1995; Lawlor‐Smith 1997; Meah 2001; Neifert 1990; Nicholson 1993; Schurz 1978).
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Twelve trials were about various aspects of breastfeeding not related to preventing mastitis (Bystrova 2007; Feng 2019; Filteau 1999; Forster 2004; Frank 1987; Gunn 1998; Homer 2001; Kramer 2001; Lumley 2006; Mastromarino 2015; Swift 2003; Waldenstrom 1994).
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Six trials were about preventing or treating breast engorgement (McLachlan 1991; NCT03230760; Nikodem 1993; Phillips 1975; Roberts 1995; Roberts 1998).
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One trial investigated prevention of subclinical mastitis (Gomo 2003).
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One trial investigated antibiotic prophylaxis for caesarean section (Luttkus 1997).
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Two trials were about the relationship between HIV and mastitis (ISRCTN98567612; Zadrozny 2017).
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Seven trials were about the prevention or treatment of breast or nipple pain or nipple damage (Centuori 1999; Dennis 2012; Gensch 2006; Harvey [date of communication?]; Herd 1986; Maldonado‐Lobon 2015; Nicholson 1985.
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Five trials were about the treatment not the prevention of mastitis (Crepinsek 2008, Hager 1996; Kvist 2004; Kvist 2007; Thomsen 1984).
Risk of bias in included studies
Figure 2 and Figure 3 summaries the risk of bias in the included studies.
Summary of risk of bias assessment of included studies.
Risk of bias judgements
Allocation
Eight of the trials reported adequate sequence generation methods and we judged them at low risk of selection bias for random sequence generation (Amir 2004; Bond 2018; De Oliveira 2006; Fernandez 2016; Hurtado 2017; Livingstone 1999; Sebitloane 2008; Svensson 2004). The remaining two did not provide sufficient information about their randomisation processes so we judged them as having unclear risk of bias (Fang 2016; He 2015).
Four trials also reported adequate methods for concealing allocation so we judged them as having low risk of bias for allocation concealment (Amir 2004; Bond 2018; Livingstone 1999; Sebitloane 2008); the remaining trials were judged to have an unclear risk of bias in regard to allocation concealment because of a lack of information reported in the published papers.
Blinding
Six trials were judged to be at low risk of performance bias because they used blinding for participants and caregivers (Amir 2004; Bond 2018; Fernandez 2016; Hurtado 2017; Sebitloane 2008; Svensson 2004).
Due to the nature of the interventions in three trials (De Oliveira 2006; Fang 2016; He 2015), it was not possible to use blinding for participants or caregivers. It is unclear if lack of blinding could have affected outcomes, therefore these trials were judged as having unclear risk of performance bias.
One trial (Livingstone 1999) explicitly stated that it did not use blinding for participants or caregivers and, therefore, was judged to be at high risk of performance bias.
Six trials were judged to be low risk of detection bias because investigators and outcome assessors were blinded (Bond 2018; De Oliveira 2006; Fernandez 2016; Hurtado 2017; Sebitloane 2008; Svensson 2004).
In four trials, the risk of detection bias was unclear because the authors did not report any details about blinding of outcome assessors (Amir 2004; Fang 2016; He 2015; Livingstone 1999).
Incomplete outcome data
We judged nine studies to have a low risk of attrition bias because they either reported complete data on all participants or had non‐differential attrition (Amir 2004; De Oliveira 2006; Fang 2016; Fernandez 2016; He 2015; Hurtado 2017; Livingstone 1999; Sebitloane 2008; Svensson 2004). There were no results available for the Bond 2018 trial, therefore, the risk of attrition bias was unclear.
Selective reporting
Most trials were judged to be at low risk of reporting bias because they appeared to report all outcomes that were prespecified. However, the results of the Bond 2018 trial were unavailable due to restrictions imposed by the probiotics provider, therefore, we judged this trial to be at high risk of reporting bias. Another trial (Fernandez 2016) was also judged to be at high risk of reporting bias because they did not report outcomes according to the full length of follow‐up that was prespecified in the trial protocol. Another trial was judged to be at high risk of reporting bias because it did not report all outcomes in full (Hurtado 2017).
Other potential sources of bias
We judged eight trials to be at low risk of other bias because there was no suggestion of any other sources of bias (Amir 2004; De Oliveira 2006; Fang 2016; Fernandez 2016; He 2015; Livingstone 1999; Sebitloane 2008; Svensson 2004).
The risk of other bias was unclear in one trial (Bond 2018) because the study authors could not provide a full paper or any results data due to restrictions imposed by the intervention manufacturer; therefore, we did not have sufficient information to judge whether there were any other sources of bias. We judged another trial to be unclear in terms of risk of other bias because we did not have sufficient information to assess whether the authors' paid work for the patent owner of the intervention could have any influence on the results (Hurtado 2017).
Effects of interventions
See: Summary of findings 1 Probiotics compared to placebo for preventing mastitis after childbirth; Summary of findings 2 Antibiotics compared to usual care or placebo for preventing mastitis after childbirth; Summary of findings 3 Antibiotics compared to topical treatments for preventing mastitis after childbirth; Summary of findings 4 Topical treatments compared to breastfeeding advice for preventing mastitis after childbirth; Summary of findings 5 Mupirocin ointment compared to fusidic acid ointment for preventing mastitis after childbirth; Summary of findings 6 Specialist breastfeeding education compared to usual care for preventing mastitis after childbirth; Summary of findings 7 Hydrothermally processed cereal with anti‐secretory factor‐inducing properties versus standard cereal standard cereal for preventing mastitis after childbirth; Summary of findings 8 Acupoint massage compared to routine care for preventing mastitis after childbirth; Summary of findings 9 Breast massage and low frequency pulse treatment compared to routine care for preventing mastitis after childbirth
Comparison one: probiotics versus placebo
Three trials compared probiotics to placebo (Bond 2018; Fernandez 2016; Hurtado 2017). We could not include data from the Bond 2018 trial (639 women) because the probiotics provider would not allow the results to be made public.
Primary outcomes
Incidence of mastitis within six months postpartum
Probiotics may reduce the risk of mastitis more than placebo (risk ratio (RR) 0.51, 95% confidence interval (CI) 0.35 to 0.75; 399 women; studies = 2; I2 = 0%; Analysis 1.1; summary of findings Table 1; low‐certainty evidence).
Recurrence of mastitis within 12 months postpartum
Not reported.
Secondary outcomes
Breast abscess within six months postpartum
Not reported.
Nipple damage within six months postpartum
One study reported the number of women using topical treatment for nipple cracks. We are uncertain if there is any effect on the risk of nipple damage with probiotics compared with placebo (RR 0.33, 95% CI 0.11 to 1.01; participants = 424; studies = 1; very low‐certainty evidence; summary of findings Table 1; Analysis 1.2; Hurtado 2017).
Duration of exclusive breastfeeding
Not reported.
Duration of any breastfeeding
Not reported.
Breast pain
It is uncertain if probiotics reduce the risk of breast pain because the certainty of evidence is very low (RR 0.81, 95% CI 0.64 to 1.01; 335 women; studies = 2; I2 = 50%) (summary of findings Table 1; Analysis 1.3; Fernandez 2016; Hurtado 2017).
Since there was some suggestion of statistical heterogeneity in the analysis, we also undertook random‐effects meta‐analysis but the effect estimate did not change substantially (RR 0.86, 95% CI 0.68, 1.09).
Breast engorgement
Not reported.
Women's perception of milk supply
Not reported.
Maternal breastfeeding satisfaction
Not reported.
Maternal breastfeeding confidence
Not reported.
Cessation of breastfeeding within six months postpartum
Not reported.
Number of women with adverse events
One study reported no women in either the probiotics group or the placebo group experienced adverse events (Fernandez 2016).
Comparison two: antibiotics versus usual care or placebo
Two trials compared antibiotics with placebo (Amir 2004 used flucloxacillin; and Sebitloane 2008 used intravenous cefoxitin in HIV‐infected women). Another trial (Livingstone 1999) compared oral cloxacillin/erythromycin with breastfeeding advice alone.
Primary outcomes
Incidence of mastitis within six months postpartum
There may be little or no difference between antibiotics and placebo or breastfeeding advice in terms of risk of mastitis although the CIs were wide and are consistent with both important benefit and harm (RR 0.37, 95% CI 0.10 to 1.34; 3 studies; 429 women; Analysis 3.1; summary of findings Table 2; low‐certainty evidence).
Recurrence of mastitis within 12 months postpartum
Not reported.
Secondary outcomes
Breast abscess within six months postpartum
Not reported.
Nipple damage within six months postpartum
Not reported.
Duration of breastfeeding
Not reported.
Duration of any breastfeeding
Not reported.
Breast pain
Five women in one trial (Livingstone 1999) had "severe sore nipples with deep, radiating, burning breast pain and episodic vasospasms of their nipples unrelated to immediate suckling". However, the trial did not report which intervention groups these women were assigned to.
Breast engorgement
Not reported.
Women's perception of milk supply
Not reported.
Duration of exclusive breastfeeding
Not reported.
Duration of any breastfeeding
Not reported.
Maternal breastfeeding satisfaction
Not reported.
Maternal breastfeeding confidence
Not reported.
Cessation of breastfeeding within six months postpartum
Not reported.
Number of women with adverse events
Not reported.
Comparison three: antibiotics versus topical treatments
One trial (Livingstone 1999) compared oral cloxacillin/erythromycin (19 women) with topical 2% mupirocin ointment (25 women) and with topical fusidic acid (17 women).
Primary outcomes
Incidence of mastitis within six months postpartum
It is uncertain whether antibiotics reduce the risk of mastitis compared to either fusidic acid ointment (RR 0.22, 95% CI 0.03 to 1.81; 36 women; studies = 1) or mupirocin ointment (RR 0.44, 95% CI 0.05 to 3.89; 44 women; studies = 1) because the certainty of evidence is low and the CIs are wide, indicating that the true effect may be either appreciable harm or appreciable benefit (Analysis 2.1; summary of findings Table 3).
Recurrence of mastitis within 12 months postpartum
Not reported.
Secondary outcomes
Not reported.
Comparison four: topical treatments versus usual care
One trial (Livingstone 1999) compared topical treatments (topical 2% mupirocin (25 women) and topical fusidic acid (17 women) to usual care in the form of optimal breastfeeding advice (23 women).
Primary outcomes
Incidence of mastitis within six months postpartum
It is uncertain whether either fusidic acid ointment (RR 0.77, 95% CI 0.27 to 2.22; 40 women; studies = 1) or mupirocin ointment (RR 0.39, 95% CI 0.12 to 1.35; 48 women; studies = 1) reduce the risk of mastitis more than optimal breastfeeding advice because the certainty of evidence is low and the CIs were wide, indicating that the true effect may be either appreciable harm or appreciable benefit (summary of findings Table 4; Analysis 4.1).
Secondary outcomes
Not reported.
Comparison five: mupirocin ointment versus fusidic acid ointment
One trial (Livingstone 1999) compared two different topical treatments to each other: 2% mupirocin ointment (25 women) and fusidic acid (17 women).
Primary outcomes
Incidence of mastitis within six months postpartum
It is uncertain if there is any difference in risk of mastitis between fusidic acid ointment and mupirocin ointment because the certainty of evidence is low and the CIs were wide, indicating that the true effect may be either appreciable harm or appreciable benefit (RR 0.51, 95% CI 0.13 to 2.00; 42 women; studies = 1; summary of findings Table 5; Analysis 5.1).
Recurrence of mastitis within 12 months postpartum
Not reported.
Secondary outcomes
Not reported.
Comparison six: specialist breastfeeding education versus usual care
One trial (De Oliveira 2006) compared specialist breastfeeding education (74 women) with usual care (137 women).
Primary outcomes
Incidence of mastitis within six months postpartum
It is uncertain if there is a difference in the risk of mastitis comparing specialist breastfeeding education with usual care because the certainty of evidence is low and the CIs were consistent with both appreciable benefit and harm (RR 0.93, 95% CI 0.17 to 4.95; 203 women; studies = 1; summary of findings Table 6; Analysis 6.1; De Oliveira 2006).
Recurrence of mastitis within 12 months postpartum
Not reported.
Secondary outcomes
Breast abscess within six months postpartum
Not reported.
Nipple damage within six months postpartum
Not reported.
Duration of exclusive breastfeeding
No trials reported duration of exclusive breastfeeding but one trial comparing specialist breastfeeding education with usual care (De Oliveira 2006) reported the rate of exclusive breastfeeding. At seven days' follow‐up, 60/73 in the breastfeeding education group were exclusively breastfeeding, compared to 109/137 in the usual care group (RR 1.03, 95% CI 0.90 to 1.18; 210 women; studies = 1). At 30 days' follow‐up the numbers of women exclusively breastfeeding were 38/71 and 80/132 (RR 0.88, 95% CI 0.68 to 1.14; 203 women; studies = 1) (Analysis 6.4).
Duration of any breastfeeding
Not reported.
Breast pain
It is uncertain if there is a difference in the risk of sore nipples comparing specialist breastfeeding education with usual care because the certainty of evidence is low and the CIs were consistent with both appreciable benefit and harm (RR 0.93, 95% CI 0.36 to 2.37; 203 women; studies = 1; (summary of findings Table 6; Analysis 6.2; De Oliveira 2006; 203 women).
Breast engorgement
One trial (De Oliveira 2006) found little or no difference between breastfeeding education and usual care in the numbers of women with breast engorgement (RR at 30 days' follow‐up 1.04, 95% CI 0.73 to 1.49; 203 women; studies = 1; Analysis 6.3).
Women's perception of milk supply
Not reported.
Maternal breastfeeding satisfaction
Not reported.
Maternal breastfeeding confidence
Not reported.
Cessation of breastfeeding within six months postpartum
Not reported.
Number of women with adverse events
Not reported.
Comparison seven: hydrothermally processed cereals with anti‐secretory factor‐inducing properties versus standard cereal
One trial investigated cereal intended to induce production of anti‐secretory factor (AF) compared with standard cereal (Svensson 2004).
Primary outcomes
Incidence of mastitis within six months postpartum
In a trial of 29 women comparing consumption of AF‐inducing cereal with standard cereal (Svensson 2004), 1/12 in the intervention group and 6/17 in the standard cereal group had mastitis (RR 0.24, 95% CI 0.03 to 1.72; 29 women; studies = 1; Analysis 7.1). It is uncertain if there is any difference in the risk of mastitis because the certainty of evidence is low and the CIs were consistent with both appreciable harm and benefit (summary of findings Table 7).
Recurrence of mastitis within 12 months postpartum
One trial (Svensson 2004) reported recurrence of mastitis within five weeks. Of the women who had mastitis, there was no recurrence in the AF‐inducing cereal group and recurrence in three of the six women in the standard cereal group (Analysis 7.2). It is uncertain if there is any difference in the risk of recurrence of mastitis because the certainty of evidence is low and the CIs were consistent with both appreciable harm and benefit (summary of findings Table 7).
Secondary outcomes
None of the secondary outcomes were reported.
Comparison eight: acupoint massage versus routine care
One trial investigated acupoint massage compared with routine care (He 2015).
Primary outcomes
Incidence of mastitis within six months postpartum
Acupoint massage probably reduces the risk of mastitis compared with routine care (RR 0.38, 95% CI 0.19 to 0.78; 400 women; studies = 1; summary of findings Table 8; moderate‐certainty evidence; Analysis 8.1; He 2015).
Recurrence of mastitis within 12 months postpartum
Not reported.
Secondary outcomes
Breast abscess within six months postpartum
Not reported.
Nipple damage within six months postpartum
Not reported.
Duration of breastfeeding
No trials measured duration of exclusive breastfeeding but, in one trial, the number of women exclusively breastfeeding at 42 days postpartum was 152/200 in the acupoint massage group compared to 80/200 in the usual care group (RR 1.90, 95% CI 1.58 to 2.29; 400 women; studies = 1; Analysis 8.2; He 2015).
Duration of any breastfeeding
Not reported.
Breast pain
Acupoint massage probably reduces the risk of severe breast pain compared to usual care (RR 0.13, 95% CI 0.07 to 0.23; 400 women; studies = 1; He 2015; Analysis 8.3; summary of findings Table 8; moderate‐certainty evidence).
Breast engorgement
In one trial, fewer women had breast engorgement in the acupoint massage group compared to the usual care group (RR 0.49, 95% CI 0.37 to 0.65; 400 women; studies = 1; Analysis 8.4; He 2015).
Women's perception of milk supply
In one trial, more women in the acupoint massage group rated their milk supply as 'moderate' or 'a lot' compared with the usual care group (RR 1.26, 95% CI 1.13 to 1.40; 400 women; studies = 1; Analysis 8.5; He 2015).
Maternal breastfeeding satisfaction
Not reported.
Maternal breastfeeding confidence
Not reported.
Cessation of breastfeeding within six months postpartum
Not reported.
Number of women with adverse events
Not reported.
Comparison nine: breast massage and low frequency pulse treatment versus routine care
One trial investigated breast massage and low frequency pulse treatment compared to routine care (Fang 2016).
Primary outcomes
Incidence of mastitis within six months postpartum
Breast message and low frequency pulse treatment may reduce the risk of mastitis compared with routine care (RR 0.03, 95% CI 0.00 to 0.21; 300 women; studies = 1; summary of findings Table 9; low‐certainty evidence; Analysis 9.1; Fang 2016).
Recurrence of mastitis within 12 months postpartum
Not reported.
Secondary outcomes
Breast abscess within six months postpartum
Not reported.
Nipple damage within six months postpartum
Not reported.
Duration of breastfeeding
No trials measured duration of exclusive breastfeeding but one trial reported more women were breastfeeding exclusively at the end of treatment with breast massage and low frequency pulse treatment compared with routine care group (RR 2.65, 95% CI 1.74 to 4.05; 300 women; studies = 1; Analysis 9.2; Fang 2016).
Duration of any breastfeeding
No trials measured duration of any breastfeeding but one trial reported more women in the breast message and low frequency pulse treatment were able to breastfeed at end of treatment compared to routine care (RR 1.83, 95% CI 1.57 to 2.12; 300 women; studies = 1; Analysis 9.3; Fang 2016).
Breast pain
Not reported.
Breast engorgement
Not reported.
Women's perception of milk supply
Women in the breast massage and low frequency pulse treatment group had a perception of greater milk supply than those in the routine care group (MD ‐5.55, 95% CI ‐5.90 to ‐5.20; 300 women; studies = 1; Analysis 9.4; Fang 2016).
Maternal breastfeeding satisfaction
Not reported.
Maternal breastfeeding confidence
Not reported.
Cessation of breastfeeding within six months postpartum
Fewer women in the breast message and low frequency pulse treatment group stopped breastfeeding than in the routine care group (RR 0.03, 95% CI 0.01 to 0.12; 300 women; studies = 1; Analysis 9.5; Fang 2016). The length of follow‐up was not reported.
Number of women with adverse events
Not reported.
Discussion
Summary of main results
This review included 10 studies (3034 women), all of which measured incidence of mastitis; one study reported recurrence of mastitis and some studies reported breast pain. We found very little evidence relating to recurrence of mastitis, breast abscess, nipple damage, duration of breastfeeding and adverse events.
Probiotics versus placebo
Three trials compared probiotics with placebo, however we were unable to include the data from the Bond 2018 trial (639 women) because the probiotics provider would not allow the results to be made public. When evaluating the incidence of mastitis within six months postpartum, findings suggest that probiotics may reduce the risk of mastitis more than placebo. Findings suggest that it is uncertain if probiotics reduce the risk of breast pain or nipple damage due to the very low certainty of evidence. The evidence relating to adverse events with probiotics compared with placebo is low‐certainty; only a single trial reported on this outcome and no women were reported to experience any adverse events (summary of findings Table 1).
Antibiotics versus usual care or placebo
Two trials compared antibiotics with placebo, with one trial using flucloxacillin and the other intravenous cefoxitin. A third trial compared oral cloxacillin/erythromycin with breastfeeding advice alone. Low‐certainty evidence suggests that there may be little to no difference between antibiotics and placebo or breastfeeding advice in terms of risk of mastitis. Five women in one of the trials reported "severe sore nipples with deep, radiating, burning breast pain and episodic vasospasms of their nipples unrelated to immediate suckling". However, the trial did not report to which intervention groups these women were assigned, resulting in a degree of uncertainly as to the true effect of the study intervention (summary of findings Table 2).
Antibiotics versus topical treatments
Oral cloxacillin/erythromycin were compared with topical 2% mupirocin ointment and topical fusidic acid. Findings from this study indicate that it is uncertain whether antibiotics reduce the risk of mastitis compared to either fusidic acid ointment or mupirocin ointment because the certainty of the evidence is low and the confidence intervals were wide, indicating that the true effect may be either appreciable harm or appreciable benefit (summary of findings Table 3).
Topical treatments versus usual care
It is uncertain whether either topical fusidic acid ointment or mupirocin ointment reduce the risk of mastitis more than optimal breastfeeding advice. The certainty of evidence is low and the confidence intervals were wide, indicating that the true effect may be either appreciable harm or appreciable benefit (summary of findings Table 4).
Mupirocin ointment versus fusidic acid ointment
It is uncertain if there is any difference in the risk of mastitis with the use of fusidic acid ointment compared to mupirocin ointment because the certainty of evidence is low and the confidence intervals were wide, indicating that the true effect may be either appreciable harm or appreciable benefit (summary of findings Table 5).
Specialist breastfeeding education versus usual care
It is uncertain if there is a difference in the risk of mastitis or sore nipples comparing specialist breastfeeding education with usual care because the certainty of evidence is low and the confidence intervals were consistent with both appreciable benefit and harm (summary of findings Table 6).
Anti‐secretory factor‐inducing cereal versus standard cereal
One trial compared the consumption of AF‐inducing cereal with standard cereal. The difference in the risk of mastitis is uncertain as the certainty of the evidence is low with the confidence intervals consistent with both appreciable harm and benefit. It is uncertain if there is any difference in the risk of recurrence of mastitis because again the certainty of evidence is low and the confidence intervals were consistent with both appreciable harm and benefit (summary of findings Table 7).
Acupoint massage versus routine care
Acupoint massage probably reduces the risk of mastitis and breast pain compared to routine care. No other important outcomes were reported for this comparison (summary of findings Table 8).
Breast massage and low frequency pulse treatment versus routine care
Breast massage and low frequency pulse treatment may reduce the risk of mastitis compared with routine care (summary of findings Table 9). No other important outcomes were reported for this comparison.
Overall completeness and applicability of evidence
The studies we identified involved women who are largely representative of our population of interest and therefore we consider that the evidence presented here is applicable to postpartum women who intend to breastfeed. However, the evidence remains uncertain about the effectiveness of interventions designed to prevent mastitis. Moreover, we are aware that this review does not present the complete evidence relating to probiotics for mastitis prevention because we were unable to obtain data from one of the largest studies we identified (Bond 2018) due to restrictions placed on the trial authors by the probiotics providers.
Two studies were stopped prematurely. One study was abandoned after 12 months due to insufficient recruitment of participants, as some women expressed a reluctance to take antibiotics and other women were overwhelmed with challenges they faced as new mothers (Amir 2004). The authors of this study also recognised in retrospect that a feasibility study would have been valuable prior to doing this trial. Livingstone's study also ceased prematurely, due to ethical concerns about the raised incidence of treatment failure and hence symptoms, amongst the participants that did not receive antibiotics (Livingstone 1999).
One may question whether some of the interventions used were robust enough to prevent mastitis. Svennson's study was found to have flaws regarding the consumption and preparation of the anti‐secretory factor in the cereal (intervention) used (Svensson 2004). The study by De Oliveira and colleagues provided participants with one education session with a lactation consultant; future research is warranted to determine whether the intervention may have proven more effective had there been more than a single session and further follow‐up with the lactation consultant (De Oliveira 2006). This review illustrated problems with complicated interventions requiring many steps or stages, affecting adherence. Fang 2016 (n = 300), Fernandez 2016 (n = 110), Hurtado 2017 (n = 217) had larger participant numbers, however, study design, allocation concealment, and blinding of participants are factors to be considered in the robustness of these studies.
The timing of an intervention and data collection need to be relevant to the participants, the condition measured and the outcomes expected. The study by De Oliveira and colleagues collected data measuring the incidence of mastitis at seven and 30 days within the two groups (De Oliveira 2006). De Oliveira's study may have found different results, had the measures been extended to perhaps three to six months (De Oliveira 2006). Moreover, interventions including education and breastfeeding advice may need to be delivered on an ongoing basis, rather than a single consult.
Withdrawal rates
This review included studies from a variety of countries (Australia, China, Spain, South Africa, Brazil and Sweden). Withdrawal rates were reported in eight of the 10 studies. Two of these studies reported no withdrawals, six studies reported the number of withdrawals, and two studies did not report. When a trial loses a high numbers of participants to follow‐up, this has implications for the completeness of data and evidence presented.
Strategies that can be implemented to improve retention include extended consultation time with participants during recruitment participants to explain and reinforce instruction; designing interventions such as tailoring drug regimens to patient lifestyle; frequent follow‐up when initiating or changing treatment regimens; and the use of reminder calls and alerts to keep participants focused.
Quality of the evidence
Generally, the risk of bias relating to randomisation and attrition was low but many of the studies were inadequately powered and therefore did not give precise estimates of effect. In addition to imprecision due to the small numbers of women participating in the trials, the certainty of evidence has also been downgraded for risk of bias with regard to allocation concealment, blinding, and selective reporting and also due to some evidence of indirectness. The certainty of the evidence ranged from low to very‐low certainty.
We cannot be certain about the evidence we identified relating to probiotics for mastitis prevention because the missing data from the Bond 2018 probiotics trial means that our effect estimates may change substantially should those data be made available and synthesised with the other identified data. The certainty of some of the evidence presented here may be influenced by the study funding sources but since the role of industry funders, or manufacturers who provide interventions for use in trials, remains unclear it is difficult to judge their impact on study results.
Potential biases in the review process
To reduce the risk of bias in the review process as far as possible, we conducted a comprehensive literature search without any restrictions with regard to language, date or publication status. We further reduced the risk of bias by ensuring that two authors independently carried out search result screening, data extraction, 'Risk of bias' assessment and GRADE ratings.
The lead author of this review is also the author of a study that was considered for inclusion in the review. To reduce bias, the lead author had no part in making the final decision about whether it was included or excluded.
However, problems obtaining missing trial data due to restrictions imposed by one of the probiotics manufacturers will inevitably have an impact on the extent to which we can present meaningful conclusions.
Agreements and disagreements with other studies or reviews
The current world literature generally agrees with the need for robust studies in this field. The World Health Organization (WHO 2000) recommends supporting education; prompt attention to any milk stasis and difficulties with feeding; infection control; and management of breast engorgement.
Few other reviews have examined the prevention of mastitis, but are somewhat consistent with the findings of a Cochrane Review of 24 trials (Lumbiganon 2016), which did not find prenatal education to be more effective than usual care in extending the duration of breastfeeding.
Few studies compared acupoint massage, but a Cochrane Review (Mangesi 2016) found acupressure to be less effective than hot and cold compresses in reducing pain from engorgement.
A recent systematic review (Anderson 2019) found that types of breast massage were reported as effective in reducing immediate pain but methods were too inconsistent to be able to draw conclusions. It recommended development of a validated tool for measuring breastfeeding problems. Another review (Pustotina 2016) compared various international guidelines and reviews, concluding that active emptying of the breasts can prevent mastitis.
Whereas Pustotina 2016 concluded that antibiotics were effective in the treatment of mastitis, a Cochrane Review (Jahanfar 2013) found insufficient evidence on the effectiveness of antibiotic therapy for the treatment of lactational mastitis, which is more consistent with our findings.
The use of probiotics is an area of growing interest but the literature has not provided sufficient data to compare with the results of this review.
Study flow diagram.
Summary of risk of bias assessment of included studies.
Risk of bias judgements
Comparison 1: Probiotics versus placebo, Outcome 1: Incidence of mastitis within 6 months postpartum
Comparison 1: Probiotics versus placebo, Outcome 2: Nipple damage within 6 months postpartum
Comparison 1: Probiotics versus placebo, Outcome 3: Breast pain
Comparison 1: Probiotics versus placebo, Outcome 4: Number of women with adverse events
Comparison 2: Antibiotics versus topical treatments, Outcome 1: Incidence of mastitis within 6 months postpartum
Comparison 3: Antibiotics versus placebo or usual care, Outcome 1: Incidence of mastitis within 6 months postpartum
Comparison 4: Topical treatments versus breastfeeding advice, Outcome 1: Incidence of mastitis within 6 months postpartum
Comparison 5: Mupirocin ointment versus fusidic acid ointment, Outcome 1: Incidence of mastitis within 6 months postpartum
Comparison 6: Specialist breastfeeding education versus usual care, Outcome 1: Incidence of mastitis within 6 months postpartum
Comparison 6: Specialist breastfeeding education versus usual care, Outcome 2: Breast pain (sore nipples)
Comparison 6: Specialist breastfeeding education versus usual care, Outcome 3: Breast engorgement
Comparison 6: Specialist breastfeeding education versus usual care, Outcome 4: Exclusive breastfeeding
Comparison 7: Hydrothermally processed cereal with anti‐secretory factor‐inducing properties versus standard cereal, Outcome 1: Incidence of mastitis within 6 months postpartum
Comparison 7: Hydrothermally processed cereal with anti‐secretory factor‐inducing properties versus standard cereal, Outcome 2: Recurrence of mastitis within 12 months postpartum
Comparison 8: Acupoint massage versus routine care, Outcome 1: Incidence of mastitis within 6 months postpartum)
Comparison 8: Acupoint massage versus routine care, Outcome 2: Exclusive breastfeeding (at 42 days postpartum)
Comparison 8: Acupoint massage versus routine care, Outcome 3: Breast pain
Comparison 8: Acupoint massage versus routine care, Outcome 4: Breast engorgement
Comparison 8: Acupoint massage versus routine care, Outcome 5: Women's perception of milk supply (moderate or better)
Comparison 9: Breast massage and low frequency pulse treatment versus routine care, Outcome 1: Incidence of mastitis within 6 months postpartum
Comparison 9: Breast massage and low frequency pulse treatment versus routine care, Outcome 2: Exclusive breastfeeding
Comparison 9: Breast massage and low frequency pulse treatment versus routine care, Outcome 3: Any breastfeeding
Comparison 9: Breast massage and low frequency pulse treatment versus routine care, Outcome 4: Women's perception of milk supply (0‐14 scale; higher score = less milk supply)
Comparison 9: Breast massage and low frequency pulse treatment versus routine care, Outcome 5: Cessation of breastfeeding (at end of treatment period)
| Probiotics compared to placebo for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with placebo | Risk with probiotics | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.51 | 399 | ⊕⊕⊝⊝ | ||
| 293 per 1000 | 149 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Study population | RR 0.33 (0.11 to 1.01) | 424 (1 RCT) | ⊕⊝⊝⊝ | ||
| 59 per 1000 | 19 per 1000 (6 to 59) | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Study population | RR 0.81 | 335 | ⊕⊕⊝⊝ | ||
| 522 per 1000 | 423 per 1000 | |||||
| Number of women with adverse events | In one trial no women in either the probiotics group or the placebo group experienced adverse events | 108 | ⊕⊕⊝⊝ | |||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to risk of bias: unclear allocation concealment, high risk of reporting bias, and missing data 2 Downgraded one level for indirectness: measured as number of women using topical treatment for nipple cracks 3 Downgraded one level due to risk of bias: unclear allocation concealment and high risk of selective reporting 4 Downgraded one level for imprecision: 95% confidence interval is consistent with possible benefit and possible harm 5 Downgraded two levels for imprecision: few participants and no events | ||||||
| Antibiotics compared to usual care or placebo for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with usual care or placebo | Risk with antibiotics | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.37 | 429 | ⊕⊕⊝⊝ | ||
| 37 per 1000 | 14 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse effects | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to imprecision: low event rate and wide 95% CIs indicating the true effect may be either appreciable benefit or harm | ||||||
| Antibiotics compared to topical treatments for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with topical treatments | Risk with antibiotics | |||||
| Incidence of mastitis within 6 months postpartum ‐ Antibiotics versus fusidic acid ointment | Study population | RR 0.22 | 36 | ⊕⊕⊝⊝ | ||
| 235 per 1000 | 52 per 1000 | |||||
| Incidence of mastitis within 6 months postpartum ‐ Antibiotics versus mupirocin ointment | Study population | RR 0.44 | 44 | ⊕⊕⊝⊝ | ||
| 120 per 1000 | 53 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse effects | Not reported | |||||
| 1 Downgraded two levels due to imprecision: single small trial with wide 95% CIs, indicating that the true effect may be either appreciable benefit or harm | ||||||
| Topical treatments compared to breastfeeding advice for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with breastfeeding advice | Risk with topical treatments | |||||
| Incidence of mastitis within 6 months postpartum ‐ Fusidic acid ointment versus breastfeeding advice | Study population | RR 0.77 | 40 | ⊕⊕⊝⊝ | ||
| 304 per 1000 | 234 per 1000 | |||||
| Incidence of mastitis within 6 months postpartum ‐ Mupirocin ointment versus breastfeeding advice | Study population | RR 0.39 | 48 | ⊕⊕⊝⊝ | ||
| 304 per 1000 | 119 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to imprecision: single small trial with wide 95% CIs, indicating that the true effect may be either appreciable benefit or harm | ||||||
| Mupirocin ointment compared to fusidic acid ointment for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with fusidic acid ointment | Risk with Mupirocin ointment | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.51 | 42 | ⊕⊕⊝⊝ | ||
| 235 per 1000 | 120 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to imprecision: single small trial with wide 95% CIs, indicating that the true effect may be either appreciable benefit or harm | ||||||
| Specialist breastfeeding education compared to usual care for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with usual care | Risk with specialist breastfeeding education | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.93 | 203 | ⊕⊕⊝⊝ | This outcome was measured at 30 days postpartum | |
| 30 per 1000 | 28 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain (sore nipples) | Study population | RR 0.93 | 203 | ⊕⊕⊝⊝ | ||
| 91 per 1000 | 85 per 1000 | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels due to imprecision: single small trial with wide 95% CIs, indicating that the true effect may be either appreciable benefit or harm | ||||||
| Anti‐secretory factor‐inducing cereal compared to standard cereal for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with standard cereal | Risk with anti‐secretory factor‐inducing cereal | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.24 | 29 | ⊕⊕⊝⊝ | ||
| 353 per 1000 | 85 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Study population | RR 0.39 | 7 | ⊕⊕⊝⊝ | ||
| 667 per 1000 | 260 per 1000 | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded two levels for imprecision: few participants and wide 95% CIs indicating the true effect may be either appreciable benefit or harm | ||||||
| Acupoint massage compared to routine care for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women Setting: obstetric outpatient clinic | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with routine care | Risk with acupoint massage | |||||
| Incidence of mastitis within 6 months postpartum) | Study population | RR 0.38 | 400 | ⊕⊕⊕⊝ | ||
| 130 per 1000 | 49 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported | |||||
| Breast pain | Study population | RR 0.13 | 400 | ⊕⊕⊕⊝ | ||
| 400 per 1000 | 52 per 1000 | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded one level due to unclear risk of bias across most domains | ||||||
| Breast message and low frequency pulse treatment compared to routine care for preventing mastitis after childbirth | ||||||
| Patient or population: postpartum breastfeeding women | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Certainty of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with routine care | Risk with breast message and low frequency pulse treatment | |||||
| Incidence of mastitis within 6 months postpartum | Study population | RR 0.03 | 300 | ⊕⊕⊝⊝ | ||
| 233 per 1000 | 7 per 1000 | |||||
| Recurrence of mastitis within 12 months postpartum | Not reported | |||||
| Breast abscess within 6 months postpartum | Not reported | |||||
| Nipple damage within 6 months postpartum | Not reported | |||||
| Duration of any breastfeeding | Not reported for either the duration of exclusive or any breastfeeding | |||||
| Breast pain | Not reported | |||||
| Number of women with adverse events | Not reported | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded one level due to unclear risk of selection, performance and detection bias 2 Downgraded one level for imprecision: few events | ||||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1.1 Incidence of mastitis within 6 months postpartum Show forest plot | 2 | 399 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.51 [0.35, 0.75] |
| 1.2 Nipple damage within 6 months postpartum Show forest plot | 1 | 424 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.33 [0.11, 1.01] |
| 1.3 Breast pain Show forest plot | 2 | 335 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.81 [0.64, 1.01] |
| 1.4 Number of women with adverse events Show forest plot | 1 | 108 | Risk Ratio (M‐H, Fixed, 95% CI) | Not estimable |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 2.1 Incidence of mastitis within 6 months postpartum Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 2.1.1 Antibiotics versus fusidic acid ointment | 1 | 36 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.22 [0.03, 1.81] |
| 2.1.2 Antibiotics versus mupirocin ointment | 1 | 44 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.44 [0.05, 3.89] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 3.1 Incidence of mastitis within 6 months postpartum Show forest plot | 3 | 429 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.37 [0.10, 1.34] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 4.1 Incidence of mastitis within 6 months postpartum Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 4.1.1 Fusidic acid ointment versus breastfeeding advice | 1 | 40 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.77 [0.27, 2.22] |
| 4.1.2 Mupirocin ointment versus breastfeeding advice | 1 | 48 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.39 [0.12, 1.35] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 5.1 Incidence of mastitis within 6 months postpartum Show forest plot | 1 | 42 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.51 [0.13, 2.00] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 6.1 Incidence of mastitis within 6 months postpartum Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 6.1.1 At hospital discharge | 1 | 211 | Risk Ratio (M‐H, Fixed, 95% CI) | Not estimable |
| 6.1.2 At 7 days | 1 | 210 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.75 [0.35, 40.70] |
| 6.1.3 At 30 days | 1 | 203 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.93 [0.17, 4.95] |
| 6.2 Breast pain (sore nipples) Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 6.2.1 At hospital discharge | 1 | 211 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.99 [0.72, 1.36] |
| 6.2.2 At 7 days | 1 | 210 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.66, 1.22] |
| 6.2.3 At 30 days | 1 | 203 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.93 [0.36, 2.37] |
| 6.3 Breast engorgement Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 6.3.1 At hospital discharge | 1 | 211 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.61 [0.03, 14.87] |
| 6.3.2 At 7 days | 1 | 210 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.04 [0.71, 1.53] |
| 6.3.3 At 30 days | 1 | 203 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.04 [0.73, 1.49] |
| 6.4 Exclusive breastfeeding Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 6.4.1 At 7 days | 1 | 210 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.03 [0.90, 1.18] |
| 6.4.2 At 30 days | 1 | 203 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.88 [0.68, 1.14] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 7.1 Incidence of mastitis within 6 months postpartum Show forest plot | 1 | 29 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.24 [0.03, 1.72] |
| 7.2 Recurrence of mastitis within 12 months postpartum Show forest plot | 1 | 7 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.39 [0.03, 4.57] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 8.1 Incidence of mastitis within 6 months postpartum) Show forest plot | 1 | 400 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.38 [0.19, 0.78] |
| 8.2 Exclusive breastfeeding (at 42 days postpartum) Show forest plot | 1 | 400 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.90 [1.58, 2.29] |
| 8.3 Breast pain Show forest plot | 1 | 400 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.12 [0.07, 0.23] |
| 8.4 Breast engorgement Show forest plot | 1 | 400 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.49 [0.37, 0.65] |
| 8.5 Women's perception of milk supply (moderate or better) Show forest plot | 1 | 400 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.26 [1.13, 1.40] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 9.1 Incidence of mastitis within 6 months postpartum Show forest plot | 1 | 300 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.03 [0.00, 0.21] |
| 9.2 Exclusive breastfeeding Show forest plot | 1 | 300 | Risk Ratio (M‐H, Fixed, 95% CI) | 2.65 [1.74, 4.05] |
| 9.3 Any breastfeeding Show forest plot | 1 | 300 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.83 [1.57, 2.12] |
| 9.4 Women's perception of milk supply (0‐14 scale; higher score = less milk supply) Show forest plot | 1 | 300 | Mean Difference (IV, Fixed, 95% CI) | ‐5.55 [‐5.90, ‐5.20] |
| 9.5 Cessation of breastfeeding (at end of treatment period) Show forest plot | 1 | 300 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.03 [0.01, 0.12] |
