Methods of term labour induction for women with a previous caesarean section

Abstract

Induction of labour is a common obstetric intervention, with between 20% and 30% of births reported to occur following induction of labour. Women with a prior caesarean delivery have an increased risk of uterine rupture, particularly when labour is induced. For women who have had a previous caesarean birth and who require induction of labour in a subsequent pregnancy, it is unclear which method of cervical ripening and labour induction is preferable. To assess the benefits and harms associated with different methods used to induce labour in women who have had a previous caesarean birth and require induction of labour in a subsequent pregnancy. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 July 2012) and reference lists of retrieved studies. All randomised controlled trials comparing any method of third trimester cervical ripening or labour induction, with placebo/no treatment or other methods in women with prior caesarean section requiring labour induction in a subsequent pregnancy were included.Methods of cervical ripening or labour induction could include: prostaglandin medication (including oral or vaginal prostaglandin E2 (PGE2) and misoprostol); mifepristone; mechanical methods (including Foley catheters and double balloon catheters); oxytocin, or placebo. The two review authors independently assessed studies for inclusion and trial quality. Any disagreement was resolved by discussion. Both review authors independently extracted data and data were checked for accuracy. Two studies (involving a total of 80 women) were included. However, the two included studies used different methods and thus, meta-analysis was not appropriate. The two included studies compared 2.5 mg vaginal PGE2 inserts versus oxytocin (Taylor and colleagues) and misoprostol versus oxytocin (Wing and colleagues). Risk of bias in the included studies was judged 'low' and 'unclear' respectively.Vaginal PGE2 inserts versus oxytocin - Taylor and colleagues included 42 women, equally distributed over both groups. Baseline characteristics, and reasons for labour induction were comparable between the groups. There were no significant differences in any of the outcome measures reported (caesarean section, instrumental vaginal deliveries, epidural analgesia, Apgar score, perinatal death). One uterine rupture occurred in the prostaglandin group, after the use of prostaglandins and oxytocin, while no ruptures occurred in the oxytocin group (one study, 42 women; risk ratio (RR) 3.00, 95% confidence interval (CI) 0.13 to 69.70).Misoprostol versus oxytocin - the study conducted by Wing and colleagues was stopped prematurely due to safety concerns after the inclusion of 38 women. Seventeen women had been included in the misoprostol group, and 21 women in the oxytocin group. There were no significant difference in the only outcome measure reported by the authors, uterine rupture, which occurred twice in the misoprostol group, and did not occur in the oxytocin group (one study; 38 women; RR 6.11, 95% CI 0.31 to 119.33). There is insufficient information available from randomised controlled trials on which to base clinical decisions regarding the optimal method of induction of labour in women with a prior caesarean birth.