There is not enough evidence about the effects of amniotomy alone (deliberate rupture of the membranes) to induce labour.
Sometimes it is advisable to get labour started (induction) because of concerns about either the pregnant woman or her unborn baby. Amniotomy has been used as either the only method of inducing labour if the membranes can be reached, or used with drugs such as oxytocin or prostaglandin. Amniotomy may be preferred by women wanting a drug-free labour and it is cheap. However, it can be uncomfortable and, if after amniotomy there is a long time interval before the baby is born, there is a risk of infection. There is also the risk of the cord coming out before the baby. This review of trials found that there is not enough evidence about the effects of amniotomy alone for the induction of labour.
Data are lacking about the value of amniotomy alone for induction of labour. While there are now other modern methods available for induction of labour (pharmacological agents), there remain clinical scenarios where amniotomy alone may be desirable and appropriate, and this method is worthy of further research. This research should include evaluation of the appropriate time interval from amniotomy to secondary intervention, women and caregivers' satisfaction and economic analysis.
[Note: the two citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]
Amniotomy (deliberate rupture of the membranes) is a simple procedure which can be used alone for induction of labour if the membranes are accessible, thus avoiding the need for pharmacological intervention. However, the time interval from amniotomy to established labour may not be acceptable to clinicians and women, and in a number of cases labour may not ensue. This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology.
To determine the effects of amniotomy alone for third trimester labour induction in women with a live fetus.
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register and bibliographies of relevant papers (January 2007). We updated this search on 23 May 2012 and added the results to the awaiting classification section of the review.
Clinical trials comparing amniotomy alone for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods.
A strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction. We assessed trial quality and contacted study authors for additional information.
Two trials, comprising 50 and 260 women, respectively were eligible for inclusion in this review. No conclusions could be drawn from comparisons of amniotomy alone versus no intervention, and amniotomy alone versus oxytocin alone (small trial, only one pre-specified outcome reported). No trials compared amniotomy alone with intracervical prostaglandins. One trial compared amniotomy alone with a single dose of vaginal prostaglandins for women with a favourable cervix, and found a significant increase in the need for oxytocin augmentation in the amniotomy alone group (44% versus 15%; relative risk 2.85, 95% confidence interval 1.82 to 4.46). This should be viewed with caution as this was the result of a single-centre trial. Furthermore, secondary intervention occurred four hours after amniotomy, and this time interval may not have been appropriate.