Vaginal prostaglandin (PGE2 and PGF2a) for induction of labour at term
Abstract
Background
Prostaglandins have been used for induction of labour since the 1960s. Initial work focused on prostaglandin F2a as prostaglandin E2 was considered unsuitable for a number of reasons. With the development of alternative routes of administration, comparisons were made between various formulations of vaginal prostaglandins. This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology.
Objectives
To determine the effects of vaginal prostaglandins E2 and F2a for third trimester cervical ripening or induction of labour in comparison with placebo/no treatment or other vaginal prostaglandins (except misoprostol).
Search methods
The Cochrane Pregnancy and Childbirth Group trials register (May 2003) and bibliographies of relevant papers.
Selection criteria
Clinical trials comparing vaginal prostaglandins used 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.
Data collection and analysis
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.
Main results
In total, 101 studies were considered: 43 excluded and 57 (10,039 women) included. One study is awaiting assessment.
Vaginal prostaglandin E2 compared with placebo or no treatment reduced the likelihood of vaginal delivery not being achieved within 24 hours (18% versus 99%, relative risk (RR) 0.19, 95% confidence interval (CI) 0.14 to 0.25, 2 trials, 384 women), there was no evidence of a difference between caesarean section rates although the risk of uterine hyperstimulation with fetal heart rate changes was increased (4.6% versus 0.51%, RR 4.14, 95% CI 1.93 to 8.90, 13 trials, 1203 women).
Comparison of vaginal prostaglandin F2a with placebo showed similar caesarean section rates but the cervical score was more likely to be improved (15% versus 60%, RR 0.25, 95% CI 0.13 to 0.49, 5 trials, 467 women), and the risk of oxytocin augmentation reduced (53.9% versus 89.1%, RR 0.60, 95% CI 0.43 to 0.84, 11 trials, 1265 women) with the use of vaginal PGF2a.
There were insufficient data to make meaningful conclusions for the comparison of vaginal PGE2 and PGF2a.
PGE2 tablet, gel and pessary appear to be as efficacious as each other. Lower dose regimens, as defined in the review, appear as efficacious as higher dose regimens.
Authors' conclusions
The primary aim of this review was to examine the efficacy of vaginal prostaglandin E2 and F2a. This is reflected by an increase in successful vaginal delivery rates in 24 hours, no increase in operative delivery rates and significant improvements in cervical favourability within 24 to 48 hours.
Further research is needed to quantify the cost‐analysis of induction of labour with vaginal prostaglandins, with special attention to different methods of administration.
PICOs
Plain language summary
Vaginal prostaglandin (PGE2 and PGF2a) for induction of labour at term
Not enough evidence to measure the effectiveness and safety of prostaglandins to ripen the cervix (neck of the uterus) and bring on labour.
Prostaglandins are produced naturally by the body and ripen the cervix and bring on labour. If needed, synthetic prostaglandins can be used via the vagina as tablets, gels, suppositories and pessaries. There is a wide variation in the doses and cost of the various types of medication. The review of trials found that using prostaglandins did not increase the need for caesareans, and caused minimal complications and that low doses were as effective as higher doses. There was not enough evidence to compare the different types and more research is needed into the safety and effectiveness of prostaglandins.
