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Biofeedback for pain during labour

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Abstract

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

To examine the effectiveness of the use of biofeedback in prenatal lessons for managing pain during labour.

Background

Labour is often a normal physiological process for women; however, it is often associated with pain and discomfort. Pain experienced by pregnant women during labour is caused by contractions of the uterus, dilatation of the cervix and, at the end of the first stage and during the second stage of labour by vaginal and pelvic floor dilatation to accommodate the baby. Pain, however, is not simply a consequence of the physiological process of delivery. Instead, pain during labour is a result of a complex and subjective interaction of multiple factors (psychological, social, physiological, and spiritual), which are related to the personal interpretation each woman may give to the feelings and physical stimuli they experience during labour and delivery. Therefore, pain and discomfort during labour should be understood within a multi‐dimensional framework. Nevertheless, complete pain relief does not necessarily mean that delivery may be a more satisfactory experience for pregnant women.

Pain and discomfort management during labour include a wide range of therapeutic strategies, both pharmacological (anaesthesia, analgesia, homeopathy, etc) and nonpharmacological (yoga, biofeedback, Tai Chi, relaxation and breathing techniques, changing positions, immersion in a birthing pool, transcutaneous electrical nerve stimulation, and other things women can do for themselves), some of which are covered in other Cochrane Reviews (Johnston 2002; Smith 2003).

The term feedback was first used in electronics to describe a feedback system by means of which information about part of a system is recorded and feeds back on that system to adjust its functioning. A typical example of a feedback mechanism is that of a thermostat (Bartholomew 1994; Burton 1993).

Biofeedback or biological feedback encompasses a therapeutic technique by which individuals receive training to improve their health and wellbeing through signals coming from their own bodies (temperature, heart rate, muscular tension, etc). The underlying principle is that changes in thoughts and emotions may result in changes in body functioning. It consists of an alternative treatment that aims to gain control over physiological responses with the aid of electronic instruments, under the supervision of experts in biofeedback technique. This includes electromyographs measuring muscle tension; skin temperature gauges showing changes in the amount of heat given off by the skin indicating a change in blood flow; galvanic skin response sensors which use the amount of sweat you produce under stress to measure the conductivity of your skin; electroencephalographs which measure brainwave activity; electrocardiographs which monitor the heart rate and may be useful in relieving an overly rapid heartbeat and controlling high blood pressure. Respiration feedback devices concentrate on the rate, rhythm, and type of breathing to help lessen symptoms of asthma, anxiety, and hyperventilation, and also promote relaxation (Reader's 1993; Rosenfeld 1996).

As a behavioral therapy, biofeedback is used to address problems related to stress, by teaching the individual to consciously regulate both psychological and physical processes and functions which are not usually under conscious control (St James 1982; St James 1983), for example, insomnia, bruxism (grinding and clenching of the teeth), asthma, constipation, fecal and urinary incontinence, irritable bowel syndrome, Raynaud's Disease (symptoms of digital ischaemia), high blood pressure, headache and chronic pain (Anonymous 1996; Mahony 2004).

These functions are part of the autonomic system and commonly operate at a subconscious level so most people are unaware of them. However, body functions are translated through sensors into a signal, which participants may see or hear, which is then recorded in a reading machine. For example, when people's muscles relax, they see a slight glittering or hear a low sound; when their muscles tense, they hear a loud sound or see a quick flash. Participants are trained to be able to modify a body function by trial and error using continuous feedback by means of what is known as a 'directed learning process'. With practice, they may learn to relax specific muscles, thereby changing a loud sound into a low sound. When participants are aware of a particular function in their bodies, they may soon learn which type of activity they should perform to attain the desired effect, for example, slow or deep breathing.

As biofeedback is a non‐invasive therapy whose effectiveness is not yet proven, it should be administered after a medical consultation has ruled out serious symptoms or an underlying chronic disorder. It is given to pregnant women to reduce the perception of pain during labour (Duchene 1989), but its use is not very common worldwide and is predominantly used in the USA, Canada and Brazil. It usually consists of eight to 10 regular sessions from half to one hour duration and administered two, three or more times per week. Pregnant women should undergo a minimum of 10 sessions, which may be during conventional prenatal classes, but can also be applied privately in the home by the pregnant woman herself. At the first session, the woman is asked a few questions about her health and that of family members and shown how to use and apply the biofeedback equipment.

Prenatal lessons consist of diverse programmes and therapies which may be informative (Dick‐Read 1933), educational (Lamaze 1958; Stern 1971), philosophical (yoga), physical (prenatal exercise), or emotional. Some of the therapies used are: aromatherapy, music therapy, massage therapy, or relaxation therapy, etc. Each of these components is administered alone or in combination, with varying frequency. They are aimed at healthy pregnant women likely to have a normal birth. If the pregnant woman is thought to have complications during the delivery, probably other pharmacological methods of pain control will be available. Although the chances are higher, even a normal pregnancy does not always lead to a normal labour and birth. Lessons are recommended by healthcare providers, or the women themselves and their partners decide themselves to attend. A number of reports confirm prenatal lessons are offered by healthcare systems or private health insurance companies in many countries such as the United States, Canada, Mexico, Brazil, Finland, Germany, Australia, Japan and China (Gagnon 2000). Prenatal lessons are generally delivered by healthcare professionals such as clinicians, nurses, physiotherapists, midwives or birth instructors. There is a need to study the effectiveness of biofeedback as a tool to reduce the perception of pain as well as the costs associated with its application.

Objectives

To examine the effectiveness of the use of biofeedback in prenatal lessons for managing pain during labour.

Methods

Criteria for considering studies for this review

Types of studies

Randomised controlled trials. Quasi‐randomised trials will be excluded.

Types of participants

Women with low‐risk pregnancies eligible to receive biofeedback in the antenatal period.

Types of interventions

The trial group will consist of prenatal lessons delivered with any content including biofeedback in whatever application mode, that is, (electromyographs, skin temperature gauges, galvanic skin response sensors, electroencephalographs, electrocardiographs, respiration feedback devices). The control intervention will consist of prenatal lessons whose contents do not include biofeedback in whatever application mode.

Types of outcome measures

Primary outcomes

(1) Women's emotional satisfaction of pain management during labour (as defined and measured by the trial authors).
(2) Pain relief during labour (as defined and measured by the trial authors).

Secondary outcomes
Mother

(3) Gestational hypertension: hypertension after 20 weeks' gestation.
(4) Induction of labour.
(5) Duration of labour in the first stage.
(6) Duration of labour in the second stage.
(7) Augmentation of labour with oxytocin.
(8) Use of pharmacological pain relief in labour.
(9) Caesarean section.
(10) Instrumental vaginal delivery.
(11) Perineal trauma (defined as episiotomy and incidence of second, third and fourth degree tears).

Neonatal

(12) Preterm birth: all births less than or equal to 37 completed weeks, and more severe prematurity, defined as less than 32 or less than 34 weeks.
(13) Apgar score less than seven at five minutes.
(14) Admission to neonatal intensive care unit or special care nursery.
(15) Long‐term neonatal complications.

Economic

(16) Cost of introducing biofeedback.
(17) Cost of hospital stay.
(18) Duration of postpartum hospital stay.

Search methods for identification of studies

Electronic searches

We will contact the Trials Search Co‐ordinator to search the Cochrane Pregnancy and Childbirth Group's Trials Register.

The Cochrane Pregnancy and Childbirth Group's Trials Register is maintained by the Trials Search Co‐ordinator and contains trials identified from:

  1. Quarterly searches of the Cochrane Central Register of Controlled Trials (CENTRAL);

  2. Monthly searches of MEDLINE;

  3. Hand searches of 30 journals and the proceedings of major conferences;

  4. Weekly current awareness search of a further 37 journals.

Details of the search strategies for CENTRAL and MEDLINE, the list of hand searched journals and conference proceedings, and the list of journals reviewed via the current awareness service can be found in the 'Search strategies for identification of studies' section within the editorial information about the Cochrane Pregnancy and Childbirth Group.

Trials identified through the searching activities described above are given a code (or codes) depending on the topic. The codes are linked to review topics. The Trials Search Co‐ordinator searches the register for each review using these codes rather than keywords.

In addition, we will search MEDLINE (1966 to present), EMBASE (1974 to present), CINAHL (1982 to present) and ERIC (1966 to present) using the strategy in Appendix 1 which will be adapted for each database.

We will not apply any language restrictions.

Data collection and analysis

We will consider all studies identified by the search strategy outlined above. Both authors will assess the trials for methodological quality and appropriateness for inclusion without consideration of their results. The reasons for excluding any trials will be stated. We will know the trial author's name, institution and the source of publication. We will resolve any disagreement through discussion until consensus is reached. We will contact authors of the original trials for further details if necessary.

Assessment of methodological quality of included studies

We will assess the validity of each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2005). We will assess each study for quality of allocation of concealment, completeness to follow up and blinding in the assessment of outcome.

(1) Selection bias (randomisation and allocation concealment)

We will assign a quality score for each trial, using the following criteria:
(A) adequate concealment of allocation, such as telephone randomisation, consecutively numbered sealed opaque envelopes;
(B) unclear whether adequate concealment of allocation; such as list or table used, sealed envelopes, or study does not report any concealment approach;
(C) inadequate concealment of allocation, such as open list of random number tables, use of case record numbers, dates of birth or days of the week.

(2) Performance bias (blinding of participants, researchers and outcome assessment)

We will assess blinding using the following criteria:
(A) blinding of participants and caregiver will not be possible due to the type of intervention being assessed;
(B) blinding of outcome assessment (yes/no/unclear).

(3) Attrition bias (loss to follow up)

We will assess completeness to follow up using the following criteria:
(A) less than 5% participants excluded;
(B) 5% to 10% of participants excluded;
(C) more than 10% and less than 20% of participants excluded;
(D) more than 20% of participants excluded.

Studies with more than 20% of participants excluded will not be included in the review.

Overall quality of trials will be classified according to the following criteria:
(A) for high‐quality trials in which all criteria are met (low risk of bias);
(B) to indicate that one or more criteria are partially met, or when it is unclear whether all criteria are met (medium risk of bias);
(C) when one or more criteria are not met (high risk of bias).

Data extraction and management

We will design a form to extract data. Both authors will extract the data using the agreed form. We will resolve discrepancies through discussion. We will use the Review Manager software (RevMan 2003) to double‐enter the data.

When information regarding any of the above is unclear, we will attempt to contact authors of the original reports to provide further details.

Measures of treatment effect

We will carry out statistical analysis using the Review Manager software (RevMan 2003). We will use fixed‐effect meta‐analysis for combining data in the absence of significant heterogeneity if trials are sufficiently similar.

For dichotomous data we will present results as summary relative risk with 95% confidence intervals.

For continuous data the weighted mean difference will be used if outcomes are measured in the same way between trials. We will use the standardised mean difference to combine trials that measure the same outcome, but use different methods. If there is evidence of skewness this will be reported.

We will analyse data on an intention‐to‐treat basis. Therefore all participants with available data will be included in the analysis in the group to which they are allocated, regardless of whether or not they received the allocated intervention. If in the original reports participants are not analysed in the group to which they were randomised, and there is sufficient information in the trial report, we will attempt to restore them to the correct group.

Assessment of heterogeneity

Tests of heterogeneity between trials will be applied if appropriate using the I‐squared statistic. If we identify high levels of heterogeneity among the trials (exceeding 50%), we will explore it by prespecified subgroup analysis and perform sensitivity analysis. A random‐effects meta‐analysis will be used as an overall summary if this is considered appropriate, otherwise a descriptive analysis rather than a meta‐analysis will be performed.

Sensitivity analysis

We will perform sensitivity analysis by trial quality; excluding trials with unclear allocation concealment.

Subgroup analyses

Planned subgroup analyses classifying whole trials will be conducted by interaction tests as described by Deeks 2001. We will analyze separately and compare with each other the different modalities of biofeedback (electromyographs, skin temperature gauges and galvanic skin response sensors).