Induction of labour at or beyond 37 weeks' gestation
Information
- DOI:
- https://doi.org/10.1002/14651858.CD004945.pub5Copy DOI
- Database:
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- Cochrane Database of Systematic Reviews
- Version published:
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- 15 July 2020see what's new
- Type:
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- Intervention
- Stage:
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- Review
- Cochrane Editorial Group:
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Cochrane Pregnancy and Childbirth Group
- Copyright:
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- Copyright © 2020 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
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Cited by:
Authors
Contributions of authors
For this updated review, Philippa Middleton (PM), Emily Shepherd (ES) and Judith Gomersall (JG) applied the selection criteria, extracted data for included studies, assessed risk of bias, carried out GRADE assessments and prepared SoF tables. All five authors (PM, ES, JG, Jonathan Morris, Caroline Crowther) contributed to drafting and editing of this update.
Sources of support
Internal sources
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Robinson Research Institute, The University of Adelaide, Adelaide, Australia
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Women and Kids, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
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Liggins Institute, The University of Auckland, Auckland, New Zealand
External sources
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NHMRC: National Health and Medical Research Council, Australia
Funding for the Cochrane Pregnancy and Childbirth Australian and New Zealand Satellite
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NIHR: National Institute for Health Research, UK
NIHR Cochrane Programme Grant Project: 13/89/05 – Pregnancy and childbirth systematic reviews to support clinical
guidelines -
UNDP‐UNFPA‐UNICEF‐WHO‐World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), Department of Sexual and Reproductive Health and Research, World Health Organization, Switzerland
This review is supported by funding to Cochrane Pregnancy and Childbirth (University of Liverpool)
Declarations of interest
Philippa Middleton: none known.
Caroline A Crowther: none known.
Jonathan Morris: none known.
Emily Shepherd: none known.
Judith Gomersall: none known.
Acknowledgements
We acknowledge the support from Cochrane Pregnancy and Childbirth editorial team in Liverpool and the Australian and New Zealand Satellite of Cochrane Pregnancy and Childbirth.
We thank Therese Dowswell from Cochrane Pregnancy and Childbirth who provided support for the 2018 update. Therese assisted with data extraction, and the production of 'Summary of findings' tables.
We would like to acknowledge the contribution of Machiko Suganuma who assisted with data extraction for the 2018 update.
We would like to acknowledge the contribution of A Metin Gulmezoglu who initiated, led and assisted in the review preparation until 2016 and Emer Van Ryswyk for her contribution to a previous version of this review (Gülmezoglu 2012).
As part of the pre‐publication editorial process, this review has been commented on by three peers (an editor and two referees who are external to the editorial team), a member of our international panel of consumers and our Group's Statistical Adviser. The authors are grateful to the following peer reviewers for their time and comments: Jim Thornton, Professor of Obstetrics and Gynaecology, University of Nottingham, UK; Rory Windrom, Department of Obstetrics and Gynaecology, University of Toronto, Canada.
This project was supported by the National Institute for Health Research (NIHR), via Cochrane programme grant funding, and Cochrane Infrastructure funding to Cochrane Pregnancy and Childbirth. The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the Systematic Reviews Programme, NIHR, National Health Service or the Department of Health.
This review is supported by funding from the UNDP‐UNFPA‐UNICEF‐WHO‐World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), Department of Sexual and Reproductive Health and Research, World Health Organization to Cochrane Pregnancy and Childbirth (University of Liverpool). HRP supports and co‐ordinates research on a global scale, synthesises research through systematic reviews of literature, builds research capacity in low‐ and middle‐income countries and develops dissemination tools to make efficient use of ever‐increasing research information. In addition to its co‐sponsors, the International Planned Parenthood Federation (IPPF) and UNAIDS are both members of HRP’s governing body.
Version history
| Published | Title | Stage | Authors | Version |
| 2020 Jul 15 | Induction of labour at or beyond 37 weeks' gestation | Review | Philippa Middleton, Emily Shepherd, Jonathan Morris, Caroline A Crowther, Judith C Gomersall | |
| 2018 May 09 | Induction of labour for improving birth outcomes for women at or beyond term | Review | Philippa Middleton, Emily Shepherd, Caroline A Crowther | |
| 2012 Jun 13 | Induction of labour for improving birth outcomes for women at or beyond term | Review | A Metin Gülmezoglu, Caroline A Crowther, Philippa Middleton, Emer Heatley | |
| 2006 Oct 18 | Induction of labour for improving birth outcomes for women at or beyond term | Review | A Metin Gülmezoglu, Caroline A Crowther, Philippa Middleton | |
| 2004 Oct 18 | Induction of labour for improving birth outcomes for women at or beyond term | Protocol | A Metin Gülmezoglu, Caroline A Crowther | |
Differences between protocol and review
2020 update of the review
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The title has been changed to 'Induction of labour at or beyond 37 weeks' gestation' to reflect increasing debate about how 'term' should be defined.
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The subgroup analyses by gestational age are now reported by induction at < 40 weeks; 40 to 41 weeks; and > 41 weeks.
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We have included an additional subgroup analysis based on parity.
2018 update of the review
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We have updated the methods in line with those in the standard template used by Cochrane Pregnancy and Childbirth.
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We have omitted the outcome of vaginal birth as it is the obverse of caesarean section.
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We have used the GRADE approach to assess the quality of the body of evidence and we have included ’Summary of findings’ tables.
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We have added three new infant secondary outcomes (birthweight; birthweight > 4000 g; neonatal trauma), which were reported as non‐prespecified, but important, outcomes in the previous version of this review, in our main outcomes list.
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The secondary infant outcome 'Perinatal death (stillbirth, newborn deaths within first week)' (which is the same as the primary outcome) has been changed to two separate outcomes, 'Stillbirth' and 'Neonatal death within the first week'.
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The subgroup analyses by gestational age are now reported by induction at < 41 weeks; and at ≥ 41 weeks.
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We have added in an additional search of ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP).
In the previous (Gülmezoglu 2012) update of this review:
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The subgroup analyses by gestational age were reported by induction at 39 to 40 weeks; at 41 weeks; and at > 41 weeks.
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The methods were updated to reflect the latest Cochrane Handbook for Systematic Reviews of Interventions version (Higgins 2011).
Keywords
MeSH
Medical Subject Headings (MeSH) Keywords
- Cesarean Section [statistics & numerical data];
- Gestational Age;
- Infant Mortality;
- Intensive Care Units, Neonatal [statistics & numerical data];
- Labor, Induced [*adverse effects];
- Perinatal Death;
- *Pregnancy, Prolonged;
- Randomized Controlled Trials as Topic;
- Risk;
- Stillbirth [epidemiology];
- *Watchful Waiting;
Medical Subject Headings Check Words
Female; Humans; Infant; Infant, Newborn; Pregnancy;
PICOs
'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.1 Perinatal death.
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.2 Stillbirth.
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.3 Neonatal death.
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.5 Admission to neonatal intensive care unit.
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.9 Meconium aspiration syndrome.
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.11 Apgar score less than 7 at 5 minutes.
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.12 Birthweight (g).
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.15 Caesarean section.
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.16 Operative vaginal birth (forceps or ventouse).
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.20 Postpartum haemorrhage.
Funnel plot of comparison: 1 Labour induction versus expectant management (all trials), outcome: 1.28 Length of labour (hours).
Comparison 1: Labour induction versus expectant management (all trials), Outcome 1: Perinatal death
Comparison 1: Labour induction versus expectant management (all trials), Outcome 2: Stillbirth
Comparison 1: Labour induction versus expectant management (all trials), Outcome 3: Neonatal death
Comparison 1: Labour induction versus expectant management (all trials), Outcome 4: Birth asphyxia
Comparison 1: Labour induction versus expectant management (all trials), Outcome 5: Admission to neonatal intensive care unit
Comparison 1: Labour induction versus expectant management (all trials), Outcome 6: Neonatal convulsions
Comparison 1: Labour induction versus expectant management (all trials), Outcome 7: Neonatal encephalopathy (HIE)
Comparison 1: Labour induction versus expectant management (all trials), Outcome 8: Use of anticonvulsants
Comparison 1: Labour induction versus expectant management (all trials), Outcome 9: Meconium aspiration syndrome
Comparison 1: Labour induction versus expectant management (all trials), Outcome 10: Pneumonia
Comparison 1: Labour induction versus expectant management (all trials), Outcome 11: Apgar score less than 7 at 5 minutes
Comparison 1: Labour induction versus expectant management (all trials), Outcome 12: Birthweight (g)
Comparison 1: Labour induction versus expectant management (all trials), Outcome 13: Birthweight > 4000 g
Comparison 1: Labour induction versus expectant management (all trials), Outcome 14: Neonatal (birth) trauma
Comparison 1: Labour induction versus expectant management (all trials), Outcome 15: Caesarean section
Comparison 1: Labour induction versus expectant management (all trials), Outcome 16: Operative vaginal birth (forceps or ventouse)
Comparison 1: Labour induction versus expectant management (all trials), Outcome 17: Analgesia used
Comparison 1: Labour induction versus expectant management (all trials), Outcome 18: Perineal trauma
Comparison 1: Labour induction versus expectant management (all trials), Outcome 19: Prolonged labour
Comparison 1: Labour induction versus expectant management (all trials), Outcome 20: Postpartum haemorrhage
Comparison 1: Labour induction versus expectant management (all trials), Outcome 21: Breastfeeding
Comparison 1: Labour induction versus expectant management (all trials), Outcome 22: Maternal satisfaction
Comparison 1: Labour induction versus expectant management (all trials), Outcome 23: Maternal satisfaction
Comparison 1: Labour induction versus expectant management (all trials), Outcome 24: Length of maternal hospital stay (days)
Comparison 1: Labour induction versus expectant management (all trials), Outcome 25: Length of maternal (postnatal) stay (categories)
Comparison 1: Labour induction versus expectant management (all trials), Outcome 26: Length of neonatal hospital stay (days)
Comparison 1: Labour induction versus expectant management (all trials), Outcome 27: Length of neonatal (postnatal) stay (categories)
Comparison 1: Labour induction versus expectant management (all trials), Outcome 28: Length of labour (hours)
Comparison 2: Labour induction versus expectant management (subgroup analysis by gestational age at induction), Outcome 1: Perinatal death
Comparison 2: Labour induction versus expectant management (subgroup analysis by gestational age at induction), Outcome 2: Stillbirth
Comparison 2: Labour induction versus expectant management (subgroup analysis by gestational age at induction), Outcome 3: Admission to neonatal intensive care unit
Comparison 2: Labour induction versus expectant management (subgroup analysis by gestational age at induction), Outcome 4: Caesarean section
Comparison 2: Labour induction versus expectant management (subgroup analysis by gestational age at induction), Outcome 5: Operative vaginal birth (forceps or ventouse)
Comparison 2: Labour induction versus expectant management (subgroup analysis by gestational age at induction), Outcome 6: Perineal trauma
Comparison 3: Labour induction versus expectant management (subgroup analysis by parity), Outcome 1: Perinatal death
Comparison 3: Labour induction versus expectant management (subgroup analysis by parity), Outcome 2: Stillbirth
Comparison 3: Labour induction versus expectant management (subgroup analysis by parity), Outcome 3: Admission to neonatal intensive care unit
Comparison 3: Labour induction versus expectant management (subgroup analysis by parity), Outcome 4: Caesarean section
Comparison 3: Labour induction versus expectant management (subgroup analysis by parity), Outcome 5: Operative vaginal birth (forceps or ventouse)
Comparison 3: Labour induction versus expectant management (subgroup analysis by parity), Outcome 6: Perineal trauma (severe perineal tear)
Comparison 4: Labour induction versus expectant management (subgroup analysis by status of cervix), Outcome 1: Perinatal death
Comparison 4: Labour induction versus expectant management (subgroup analysis by status of cervix), Outcome 2: Stillbirth
Comparison 4: Labour induction versus expectant management (subgroup analysis by status of cervix), Outcome 3: Admission to neonatal intensive care unit
Comparison 4: Labour induction versus expectant management (subgroup analysis by status of cervix), Outcome 4: Caesarean section
Comparison 4: Labour induction versus expectant management (subgroup analysis by status of cervix), Outcome 5: Operative vaginal birth (forceps or ventouse)
Comparison 4: Labour induction versus expectant management (subgroup analysis by status of cervix), Outcome 6: Perineal trauma
| Induction of labour for improving birth outcomes for women at or beyond 37 weeks gestation | ||||||
| Population: pregnant women at or beyond 37 weeks gestation | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Quality of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with expectant management | Risk with labour induction | |||||
| Perinatal death (intrauterine deaths plus neonatal deaths in the first week of life) | Study population | RR 0.31 | 18,795 | ⊕⊕⊕⊕ | Exact day of death not reported for all of the nine neonatal deaths but all were likely to have occurred in the first week of life (see Table 5) | |
| 3 per 1000 | 0.4 per 1000 (0.1 to 1.9) | |||||
| Stillbirth | Study population | RR 0.30 | 18,795 | ⊕⊕⊕⊕ | ||
| 2 per 1000 | 1 per 1000 | |||||
| Admission to neonatal intensive care unit | Study population | RR 0.88 | 17,826 | ⊕⊕⊕⊕ | ||
| 95 per 1000 | 83 per 1000 | |||||
| Neonatal encephalopathy | Study population | RR 0.69 (0.37 to 1.31) | 8,851 (2 RCTs) | ⊕⊕⊝⊝ LOW 2 | ||
| 5 per 1000 | 3 per 1000 (2 to 7) | |||||
| Apgar score less than 7 at 5 minutes | Study population | RR 0.73 | 18,345 | ⊕⊕⊕⊝ | ||
| 13 per 1000 | 10 per 1000 | |||||
| Neonatal (birth) trauma | Study population | RR 0.97 | 13,106 | ⊕⊕⊕⊝ | ||
| 7 per 1000 | 7 per 1000 | |||||
| Neurodevelopment at childhood follow‐up | Study population | ‐ | (0 RCTs) | ‐ | No RCTs reported data for this outcome. | |
| see comment | see comment | |||||
| *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 | ||||||
| 1Not downgraded (larger studies (> 1000 participants) are generally at low risk of bias, although some smaller studies have unclear risk of selection bias); not downgraded for lack of blinding as unlikely to have influenced objective outcomes. 2Downgraded 2 levels for very serious concerns regarding imprecision (wide confidence intervals crossing the line of no effect). 3Downgraded 1 level for serious concerns regarding indirectness, with three studies reporting Apgar scores with more stringent cutoffs than < 5 at 7 minutes (see graph footnotes). 4Downgraded 1 level for serious concerns regarding imprecision, with wide confidence intervals crossing line of no effect. | ||||||
| Study | Cause of death | |
| Intervention Group | Control Group (Expectant management) | |
| No deaths | No deaths | |
| 1. Severe malformations (Livebirth) GA at birth and timing of death after birth not reported, but assumed to be early | 1. Malformation (Livebirth) GA at birth and timing of death after birth not reported, but assumed to be early 2. Pneumonia (Livebirth) GA at birth and timing of death after birth not reported, but assumed to be early | |
| No deaths | No deaths | |
| No deaths | 1. Congenital heart condition (Stillbirth) GA at detection of death not reported | |
| No deaths | 1. Meconium aspiration and persistent fetal circulation (Livebirth) GA at birth was 43 + 4 and timing of death after birth was early but not reported in days | |
| No deaths | 1. Cord complication (Stillbirth) GA at detection of fetal death was 40 + 3 weeks | |
| No deaths | 1. Intrauterine fetal death (Stillbirth) GA at death 41 + 5 weeks | |
| Antepartum stillbirth: 1 | Antepartum stillbirth: 1 Intrapartum stillbirth: 0 Neonatal death: 2 early deaths (no other information; time of death not reported) | |
| No deaths | 1. Hypoxic ischaemic encephalopathy (Stillbirth) GA at detection of death not reported in days 2. Massive aspiration of meconium (Stillbirth) GA at detection of death not reported | |
| No deaths | 1. Birth asphyxia secondary to a true knot in the umbilical cord (Livebirth) Birth at 294 days GA; death at 2 days of age | |
| No deaths | 1. Stillbirth in a woman with an abnormal glucose tolerance test (Stillbirth) GA at detection of death not reported 2. Neonatal death from meconium inhalation in a woman with a positive amnioscopy who refused surgical induction of labour (Livebirth) GA at detection of death not reported, but presumed early | |
| No deaths | 1. Congenital anomaly (Livebirth) Birth at 43 weeks; death at 3 days of age | |
| No deaths | No deaths | |
| One fetal death: “The stillbirth in the induction group was in a 30 year old multiparous woman who was randomised at 40 weeks+5 days and scheduled for induction at 41 weeks+1 day. She had reduced fetal movements at 40 weeks+6 days, and fetal death was diagnosed at consultation. She delivered a neonate weighing 3595 g (20th to 50th centiles). Investigations, including a postmortem examination, did not explain the stillbirth.” | 2 fetal deaths: "stillbirth was diagnosed in a 36 year old nulliparous woman at 41 weeks+3 days, when she was admitted to hospital in labour. She delivered a neonate weighing 2945 g (5th to 10th centiles). Investigations, including placental examination, did not explain the stillbirth, and the parents declined a postmortem examination. The second stillbirth in the expectant management group was diagnosed in a 32 year old multiparous woman at 41 weeks+4 days during a regular consultation in secondary care for impending post‐term pregnancy. She delivered a neonate weighing 3715 g (20th to 50th centiles). No postmortem examination was performed, but the placenta showed signs of chorioamnionitis.” | |
| No deaths reported | 1 (Stillbirth) Stillbirth after induction of labour at 42 weeks for postmaturity and meconium | |
| No deaths | No deaths | |
| No deaths | No deaths | |
| No deaths reported | No deaths reported | |
| No deaths | 1 (Intrauterine fetal death) (Stillbirth) Death detected at 42 weeks' GA | |
| No deaths | No deaths | |
| No deaths | No deaths | |
| No deaths | No deaths | |
| No deaths | 6 (5 stillbirths; 1 early neonatal death) One stillborn baby had cardiovascular malformations not considered to be lethal and there were no explanations for the deaths of the other four stillbirths; Cause of the early neonatal death was hypoxic ischaemic encephalopathy in a large for gestational age neonate. | |
| GA: gestational age | ||
| Induction of labour for improving birth outcomes for women at or beyond term | ||||||
| Population: pregnant women at or beyond 37 weeks gestation | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect | № of participants | Quality of the evidence | Comments | |
|---|---|---|---|---|---|---|
| Risk with expectant management | Risk with labour induction | |||||
| Caesarean section | Study population | RR 0.90 | 21,030 | ⊕⊕⊕⊝ | ||
| 186 per 1000 | 167 per 1000 | |||||
| Operative vaginal birth (forceps or ventouse) | Study population | RR 1.03 | 18,584 | ⊕⊕⊕⊝ | ||
| 136 per 1000 | 140 per 1000 | |||||
| Perineal trauma (severe perineal tear) | Study population | RR 1.04 | 11,589 | ⊕⊕⊝⊝ | ||
| 31 per 1000 | 33 per 1000 | |||||
| Postpartum haemorrhage | Study population | RR 1.02 | 12,609 | ⊕⊕⊕⊝ | variously defined | |
| 79 per 1000 | 81 per 1000 | |||||
| Breastfeeding at discharge | Study population | RR 1.00 (0.96 to 1.04) | 7487 (2 RCTs) | ⊕⊕⊕⊝ | ||
| 505 per 1000 | 505 per 1000 (485 to 525) | |||||
| Postnatal depression | Study population | ‐ | (0 RCTs) | ‐ | No RCTs reported data for this outcome. | |
| see comment | see comment | |||||
| Length of maternal hospital stay (days) | ‐ | ‐ | Average MD 0.19 days shorter for women who were induced | 4120 | ⊕⊝⊝⊝ VERY LOW5 | |
| *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 | ||||||
| 1Downgraded 1 level for serious concerns regarding unclear allocation concealment methods for many of the 31 trials included for this outcome. 3Downgraded 1 level for serious concerns regarding indirectness with postpartum haemorrhage defined in different ways for several of the trials. 4Downgraded 1 level for indirectness with one of the two studies reporting breastfeeding 4‐8 weeks after discharge (not at discharge). 5Downgraded 1 level for serious concerns regarding selection bias, with 4 of 5 trials having with unclear allocation concealment; and downgraded 2 levels for very serious concerns regarding inconsistency, with very high statistical heterogeneity (I² = 94%). | ||||||
| Study | At baseline/enrolment (all participants) | At induction (intervention group participants only) Mean [SD] unless otherwise indicated |
| 41 weeks (290‐297 days) | 294.8 days (category: ≥ 41 weeks) | |
| 40+6 weeks (283‐289 days) | 285.35 [0.93] days (category: 40‐41 weeks) | |
| 42 weeks+ (294+ days) | 294+ days, mean NR (category: ≥ 41 weeks) | |
| between 37+0 and 41+6 weeks | 282 [5.9] days (category: 40‐41 weeks) | |
| 37 to 39 weeks (259‐273 days) | 259‐273 days, mean NR (category: < 40 weeks) | |
| < 41 weeks (< 290 days) | < 290 days, mean NR (category: 40‐41 weeks) | |
| 41+3 weeks (290 days) | 290.4 [1.4] days (category: ≥ 41 weeks) | |
| 42+0 weeks (294 days) | 294+ days (category: ≥ 41 weeks) | |
| 39 to 40 weeks (273‐280 days) | 273‐280 days, mean NR (category: < 40 weeks) | |
| 41 weeks+ (287 days+) | 296.3 [2.6] days (category: ≥ 41 weeks) | |
| 40 weeks (280 days) | 280 days (category: 40 to 41 weeks ) | |
| 41 weeks+ 0‐1 | 286‐288 days (category: ≥ 41 weeks) | |
| 380 weeks to 386 (268‐274 days) | 390 weeks to 394 weeks (273‐279 days) (category: < 40 weeks) | |
| 41 weeks+ (287 days+) | 287 days+ mean NR (authors stated that women were induced within 4 days of enrolment, and that 88% of women were 41 weeks GA, (287‐293 days GA), no further details) (category: ≥ 41 weeks) | |
| 406 weeks (286 days) | Mean 289 [0.7] days (category: ≥ 41 weeks) | |
| 41 weeks+ (287 days+) | 287+ days, mean NR (category: ≥ 41 weeks) | |
| 42 weeks+ (294 days+) | 294+ days, mean NR (category: ≥ 41 weeks) | |
| 41 weeks (287 days) | 287+ days, mean NR (category: ≥ 41 weeks) | |
| 405 to 410 weeks (285‐287 days) | 287 to 288 days, mean NR (category: ≥ 41 weeks) | |
| 371 to 376 weeks (260‐266 days) | 273 days (category: < 40 weeks) | |
| 41 weeks (287 days) | 287+ days, mean NR (category: ≥ 41 weeks) | |
| 380 to 386 (266 to 272 days) | 390 to 396 weeks (273‐279 days), mean NR (category: < 40 weeks) | |
| 41 weeks+ (at least 287 days) | 287 days to < 301 days, mean NR (category: ≥ 41 weeks) | |
| 390 to 396 weeks (273‐279 days) | Within a week after enrolment, therefore between 39 and 40 weeks (274 to 280 days) (mean time between enrolment and induction of labour 3.7 days) (category: < 40 weeks) | |
| Unclear (due to incomplete translation of paper) | 42 completed weeks (category: ≥ 41 weeks) | |
| 410 to 416 weeks (287 to 293 days) | 42 completed weeks (category: ≥ 41 weeks) | |
| 410 to 416 weeks (287‐293 days) | 287‐293 days, mean NR (category: ≥ 41 weeks) | |
| 400 and 406 weeks | 280 to 286 days (category: 40 to 41 weeks) | |
| ≥ 39 weeks (≥ 273 days) | ≥ 273 days (category: < 40 weeks) | |
| 10 days or more post‐date | 287+ days (category: ≥ 41 weeks) | |
| At least 37 weeks (259+ days) | 40 weeks, EDD +/‐ 2 days (category: 40 to 41 weeks) | |
| 360 to 396 weeks (252‐279 days) | 390 to 396 weeks (273‐279 days) (category: < 40 weeks) | |
| 406 to 411 weeks (286 to 288 days) | 288.7 [1.1] weeks (category: ≥ 41 weeks) | |
| 41 weeks (293 to 298 days) | 42 weeks (293‐298 days) (category: ≥ 41 weeks) | |
| EDD : estimated due date | ||
| Primiparous | Mixed (primi‐ and multiparous) | Not stated/not available |
| Wennerholm 2019 (perinatal deaths reported by parity) |
| STUDY | START (hospital or home: and type of unit (obstetric or midwife‐led)) | WAITING (hospital or home) |
| Hospital "Women in group 1 (immediate induction) were then referred to the delivery department for induction" | Not reported | |
| Hospital | Not reported | |
| Hospital | Hospital (not explicitly stated that women in the induction group stayed in hospital after induction started). However authors reported that two women in the induction group (who waited up until a week for induction) stayed in hospital after randomisation, due to transport/distance issues). This suggests that some women waited at home. | |
| Hospital (Swedish delivery unit) | Hospital | |
| Unclear (in French) | Unclear (in French) | |
| Not reported | Not reported | |
| Hospital | Hospital | |
| Not reported | Not reported | |
| Hospital | Not reported | |
| Hospital | Home and hospital: women who did not have a regular contractile pattern 45 minutes after induction gel was administered were allowed to go home; those who did were admitted to the hospital. | |
| Not reported | Not reported | |
| Hospital | Hospital | |
| Not reported (A specific induction protocol was not mandated for women who underwent induction in either group). | Not reported | |
| Hospital (community and tertiary) | Not reported, only reported that when induction was started, women were treated as outpatients in the hospital | |
| Hospital | Not reported | |
| Hospital | Not reported | |
| Hospital | Home and hospital or either: women with a Bishop score > 6 stayed in hospital after the induction was performed, and sent to birthing ward; while those with a lower Bishop score were asked to go home and come in the next morning | |
| Hospital | Not reported | |
| Primary care midwifery practices (n = 123) and hospitals (n = 45) (in the Netherlands, care is provided for women with normal risk pregnancies by midwives, and for pregnancies at increased risk by obstetricians or gynaecologists) | "all women in the 41 week induction group received obstetrician led intrapartum secondary care" | |
| Hospital | Hospital | |
| Hospital | Hospital | |
| Hospital | Hospital | |
| Hospital | Hospital | |
| Hospital | Not reported | |
| Unclear (in Spanish) | Unclear (in Spanish) | |
| Hospital | Not reported | |
| Not reported | Not reported | |
| Not reported | Not reported | |
| Hospital Not stated by authors, however implied by the trial inclusion criteria: "persistent contractions after overnight hospitalisation > 8 h" | Not reported | |
| Hospital | Not reported | |
| "Two health clinics" | Health clinic where labour was induced | |
| Not reported: "In the induction group, local policies for induction of labor were followed". | Not reported | |
| Not reported | Not reported | |
| Hospital | Not reported |
| Week | IOL | Expectant | ||
| rate/1000 | rate/1000 | |||
| 37 | 0 | 0 | 0 | 0 |
| 38 | 0/111 | 0 | 1/117 | 8.5 |
| 39 | 2/3455 | 0.6 | 4/3443 | 1.2 |
| 40‐41 | 0/380 | 0 | 1/380 | 2.6 |
| ≥ 42 | 2/5472 | 0.37 | 19/5437 | 3.5 |
| IOL: induction of labour | ||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1.1 Perinatal death Show forest plot | 22 | 18795 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.31 [0.15, 0.64] |
| 1.2 Stillbirth Show forest plot | 22 | 18795 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.30 [0.12, 0.75] |
| 1.3 Neonatal death Show forest plot | 21 | 18611 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.39 [0.13, 1.14] |
| 1.4 Birth asphyxia Show forest plot | 4 | 1456 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.66 [0.61, 4.55] |
| 1.5 Admission to neonatal intensive care unit Show forest plot | 17 | 17826 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.88 [0.80, 0.96] |
| 1.6 Neonatal convulsions Show forest plot | 5 | 13216 | Risk Ratio (M‐H, Random, 95% CI) | 1.01 [0.15, 6.67] |
| 1.7 Neonatal encephalopathy (HIE) Show forest plot | 2 | 8851 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.69 [0.37, 1.31] |
| 1.8 Use of anticonvulsants Show forest plot | 1 | 349 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.34 [0.01, 8.17] |
| 1.9 Meconium aspiration syndrome Show forest plot | 13 | 16622 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.75 [0.62, 0.92] |
| 1.10 Pneumonia Show forest plot | 2 | 8851 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.54 [0.27, 1.06] |
| 1.11 Apgar score less than 7 at 5 minutes Show forest plot | 20 | 18345 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.73 [0.56, 0.96] |
| 1.12 Birthweight (g) Show forest plot | 18 | 8817 | Mean Difference (IV, Fixed, 95% CI) | ‐59.38 [‐77.03, ‐41.73] |
| 1.13 Birthweight > 4000 g Show forest plot | 8 | 5593 | Risk Ratio (M‐H, Random, 95% CI) | 0.72 [0.54, 0.96] |
| 1.14 Neonatal (birth) trauma Show forest plot | 5 | 13106 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.97 [0.63, 1.49] |
| 1.15 Caesarean section Show forest plot | 31 | 21030 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.85, 0.95] |
| 1.16 Operative vaginal birth (forceps or ventouse) Show forest plot | 22 | 18584 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.03 [0.96, 1.10] |
| 1.17 Analgesia used Show forest plot | 12 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 1.17.1 Epidural/regional | 8 | 4579 | Risk Ratio (M‐H, Random, 95% CI) | 1.09 [0.99, 1.20] |
| 1.17.2 Other | 4 | 2352 | Risk Ratio (M‐H, Random, 95% CI) | 1.11 [1.05, 1.18] |
| 1.18 Perineal trauma Show forest plot | 7 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 1.18.1 Severe perineal tear | 5 | 11589 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.04 [0.85, 1.26] |
| 1.18.2 Episiotomy | 2 | 1747 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.96 [0.84, 1.11] |
| 1.18.3 Obstetrical anal sphincter injuries | 2 | 1698 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.81 [0.51, 1.31] |
| 1.19 Prolonged labour Show forest plot | 4 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 1.19.1 First stage | 2 | 648 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.76 [0.49, 1.20] |
| 1.19.2 Second stage | 1 | 508 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.67 [0.36, 1.22] |
| 1.19.3 Third stage | 1 | 249 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.02 [0.12, 73.52] |
| 1.19.4 No definition | 1 | 112 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.35 [0.01, 8.30] |
| 1.20 Postpartum haemorrhage Show forest plot | 9 | 12609 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.02 [0.91, 1.15] |
| 1.21 Breastfeeding Show forest plot | 2 | 7487 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.00 [0.96, 1.04] |
| 1.22 Maternal satisfaction Show forest plot | 3 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 1.22.1 Hoping to be randomised to the same trial arm as they had been in this study | 1 | 496 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.93 [1.62, 2.30] |
| 1.22.2 Preferred/satisfied with their allocation | 2 | 493 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.99 [0.88, 1.13] |
| 1.22.3 Satisfaction with pregnancy outcome | 1 | 308 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.92 [0.80, 1.06] |
| 1.23 Maternal satisfaction Show forest plot | 1 | 619 | Mean Difference (IV, Fixed, 95% CI) | 0.07 [‐0.02, 0.16] |
| 1.24 Length of maternal hospital stay (days) Show forest plot | 7 | 4120 | Mean Difference (IV, Random, 95% CI) | ‐0.19 [‐0.56, 0.18] |
| 1.25 Length of maternal (postnatal) stay (categories) Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 1.25.1 < 2 days | 1 | 6096 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.01 [0.87, 1.17] |
| 1.25.2 2 days | 1 | 6096 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.04 [1.01, 1.08] |
| 1.25.3 3 days | 1 | 6096 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.88 [0.77, 0.99] |
| 1.25.4 4 days | 1 | 6096 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.78 [0.62, 0.97] |
| 1.25.5 > 4 days | 1 | 6096 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.94 [0.48, 1.82] |
| 1.26 Length of neonatal hospital stay (days) Show forest plot | 1 | 302 | Mean Difference (IV, Fixed, 95% CI) | ‐0.30 [‐0.61, 0.01] |
| 1.27 Length of neonatal (postnatal) stay (categories) Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 1.27.1 ≤ 2 days | 1 | 6091 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.05 [1.02, 1.08] |
| 1.27.2 ≥ 3 days | 1 | 6091 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.86 [0.79, 0.94] |
| 1.28 Length of labour (hours) Show forest plot | 12 | 4025 | Mean Difference (IV, Random, 95% CI) | ‐1.08 [‐1.67, ‐0.50] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 2.1 Perinatal death Show forest plot | 22 | 18795 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.31 [0.15, 0.64] |
| 2.1.1 < 40 weeks | 4 | 7126 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.50 [0.13, 2.01] |
| 2.1.2 40 to 41 weeks | 3 | 760 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.31 [0.01, 7.45] |
| 2.1.3 ≥ 41 weeks | 15 | 10909 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.26 [0.11, 0.64] |
| 2.2 Stillbirth Show forest plot | 22 | 18795 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.30 [0.12, 0.75] |
| 2.2.1 < 40 weeks | 4 | 7126 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.51 [0.09, 2.76] |
| 2.2.2 40 to 41 weeks | 3 | 760 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.31 [0.01, 7.45] |
| 2.2.3 ≥ 41 weeks | 15 | 10909 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.24 [0.08, 0.78] |
| 2.3 Admission to neonatal intensive care unit Show forest plot | 17 | 17826 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.88 [0.80, 0.96] |
| 2.3.1 < 40 weeks | 5 | 7409 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.79, 1.02] |
| 2.3.2 40 to 41 weeks | 3 | 527 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.68 [0.53, 5.29] |
| 2.3.3 ≥ 41 weeks | 9 | 9890 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.84 [0.74, 0.96] |
| 2.4 Caesarean section Show forest plot | 31 | 21030 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.85, 0.95] |
| 2.4.1 < 40 weeks | 8 | 8537 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.87 [0.80, 0.95] |
| 2.4.2 40 to 41 weeks | 6 | 1189 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.12 [0.88, 1.43] |
| 2.4.3 ≥ 41 weeks | 17 | 11304 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.83, 0.97] |
| 2.5 Operative vaginal birth (forceps or ventouse) Show forest plot | 22 | 18584 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.03 [0.96, 1.10] |
| 2.5.1 < 40 weeks | 7 | 8376 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.04 [0.93, 1.16] |
| 2.5.2 40 to 41 weeks | 4 | 707 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.64 [0.82, 3.29] |
| 2.5.3 ≥ 41 weeks | 11 | 9501 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.01 [0.92, 1.11] |
| 2.6 Perineal trauma Show forest plot | 5 | 11589 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.04 [0.85, 1.26] |
| 2.6.1 < 40 weeks | 2 | 6714 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.18 [0.90, 1.55] |
| 2.6.2 40 to 41 weeks | 0 | 0 | Risk Ratio (M‐H, Fixed, 95% CI) | Not estimable |
| 2.6.3 ≥ 41 weeks | 3 | 4875 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.89 [0.66, 1.19] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 3.1 Perinatal death Show forest plot | 22 | 18795 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.31 [0.15, 0.64] |
| 3.1.1 Nulliparous | 3 | 8229 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.26 [0.06, 1.05] |
| 3.1.2 Mixed (primi‐ and multiparous) | 18 | 10470 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.33 [0.14, 0.78] |
| 3.1.3 Not stated | 2 | 96 | Risk Ratio (M‐H, Fixed, 95% CI) | Not estimable |
| 3.2 Stillbirth Show forest plot | 22 | 18795 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.30 [0.12, 0.74] |
| 3.2.1 Nulliparous | 3 | 8229 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.23 [0.04, 1.35] |
| 3.2.2 Mixed (primi‐ and multiparous) | 18 | 10470 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.33 [0.12, 0.97] |
| 3.2.3 Not stated | 2 | 96 | Risk Ratio (M‐H, Fixed, 95% CI) | Not estimable |
| 3.3 Admission to neonatal intensive care unit Show forest plot | 17 | 17826 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.88 [0.80, 0.96] |
| 3.3.1 Nulliparous | 5 | 7312 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.79, 1.03] |
| 3.3.2 Mixed (primi‐ and multiparous) | 10 | 10200 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.83 [0.73, 0.95] |
| 3.3.3 Not stated | 2 | 314 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.20 [0.70, 2.06] |
| 3.4 Caesarean section Show forest plot | 31 | 21030 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.85, 0.95] |
| 3.4.1 Nulliparous | 6 | 7543 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.89 [0.81, 0.97] |
| 3.4.2 Mixed (primi‐ and multiparous) | 20 | 12877 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.83, 0.97] |
| 3.4.3 Not stated | 5 | 610 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.12 [0.81, 1.56] |
| 3.5 Operative vaginal birth (forceps or ventouse) Show forest plot | 22 | 18584 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.03 [0.96, 1.10] |
| 3.5.1 Nulliparous | 4 | 7151 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.96 [0.84, 1.09] |
| 3.5.2 Mixed (primi‐ and multiparous) | 15 | 11224 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.06 [0.97, 1.15] |
| 3.5.3 Not stated | 3 | 209 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.09 [0.58, 2.06] |
| 3.6 Perineal trauma (severe perineal tear) Show forest plot | 5 | 11589 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.04 [0.85, 1.26] |
| 3.6.1 Nulliparous | 2 | 6714 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.18 [0.90, 1.55] |
| 3.6.2 Mixed (primi‐ and multiparous) | 3 | 4875 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.89 [0.66, 1.19] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 4.1 Perinatal death Show forest plot | 22 | 18795 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.31 [0.15, 0.64] |
| 4.1.1 Favourable cervix | 3 | 760 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.31 [0.01, 7.45] |
| 4.1.2 Unfavourable cervix | 7 | 4938 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.29 [0.07, 1.17] |
| 4.1.3 Unknown/mixed state of cervix | 12 | 13097 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.32 [0.13, 0.77] |
| 4.2 Stillbirth Show forest plot | 22 | 18795 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.30 [0.12, 0.75] |
| 4.2.1 Favourable cervix | 3 | 760 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.31 [0.01, 7.45] |
| 4.2.2 Unfavourable cervix | 7 | 4938 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.27 [0.05, 1.66] |
| 4.2.3 Unknown/mixed state of cervix | 12 | 13097 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.31 [0.10, 0.95] |
| 4.3 Admission to neonatal intensive care unit Show forest plot | 17 | 17826 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.88 [0.80, 0.96] |
| 4.3.1 Favourable cervix | 2 | 475 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.02 [0.12, 73.52] |
| 4.3.2 Unfavourable cervix | 6 | 4529 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.77, 1.05] |
| 4.3.3 Unknown/mixed state of cervix | 9 | 12822 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.86 [0.77, 0.97] |
| 4.4 Caesarean section Show forest plot | 31 | 21030 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.90 [0.85, 0.95] |
| 4.4.1 Favourable cervix | 4 | 906 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.12 [0.76, 1.65] |
| 4.4.2 Unfavourable cervix | 10 | 5361 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.92 [0.83, 1.01] |
| 4.4.3 Unknown/mixed state of cervix | 17 | 14763 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.88 [0.82, 0.95] |
| 4.5 Operative vaginal birth (forceps or ventouse) Show forest plot | 22 | 18584 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.03 [0.96, 1.10] |
| 4.5.1 Favourable cervix | 3 | 655 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.87 [0.42, 1.82] |
| 4.5.2 Unfavourable cervix | 5 | 3799 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.06 [0.95, 1.18] |
| 4.5.3 Unknown/mixed state of cervix | 14 | 14130 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.01 [0.92, 1.11] |
| 4.6 Perineal trauma Show forest plot | 5 | 11589 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.04 [0.85, 1.26] |
| 4.6.1 Unknown/mixed state of cervix | 5 | 11589 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.04 [0.85, 1.26] |
