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.
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
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2009) and bibliographies of relevant papers. We updated this search on 24 February 2012 and added the results to the awaiting classification section.
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
We assessed studies and extracted data independently.
Main results
Sixty‐three (10,441 women) have been included.
Vaginal prostaglandin E2 compared with placebo or no treatment reduced the likelihood of vaginal delivery not being achieved within 24 hours (18.1% versus 98.9%, risk ratio (RR) 0.19, 95% confidence interval (CI) 0.14 to 0.25, two trials, 384 women). The risk of the cervix remaining unfavourable or unchanged was reduced (21.6% versus 40.3%, RR 0.46, 95% CI 0.35 to 0.62, five trials, 467 women); and the risk of oxytocin augmentation reduced (35.1% versus 43.8%, RR 0.83, 95% CI 0.73 to 0.94, 12 trials, 1321 women) when PGE2 was compared to placebo. There was no evidence of a difference between caesarean section rates, although the risk of uterine hyperstimulation with fetal heart rate changes was increased (4.4% versus 0.49%, RR 4.14, 95% CI 1.93 to 8.90, 14 trials, 1259 women).
PGE2 tablet, gel and pessary appear to be as efficacious as each other and the use of sustained release PGE2 inserts appear to be associated with a reduction in instrumental vaginal delivery rates (9.9 % versus 19.5%, RR 0.51, 95% CI 0.35 to 0.76, NNT 10 (6.7 to 24.0), five trials, 661 women) when compared to vaginal PGE2 gel or tablet.
Authors' conclusions
PGE2 increases successful vaginal delivery rates in 24 hours and cervical favourability with no increase in operative delivery rates. Sustained release vaginal PGE2 is superior to vaginal PGE2 gel with respect to some outcomes studied.
Further research is needed to assess the best vehicle for delivering vaginal prostaglandins and this should, where possible, include some examination of the cost‐analysis.
[Note: The 10 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]
PICOs
Plain language summary
Vaginal prostaglandin (PGE2 and PGF2a) for induction of labour at term
Vaginal prostaglandins are a safe and effective way of bringing on labour. The use of these medications is not associated with an increase in operative deliveries. Prostaglandins are produced naturally by the body. They are involved in ripening the cervix and bringing on labour. Safety concerns for the mother or baby sometimes make it necessary to bring on labour artificially. Synthetic prostaglandins can be used and are available as vaginal tablets, gels, suppositories and pessaries. The induction regimens with number of applications, dosages, and time intervals between doses vary considerably. Sustained release pessaries reduce the number of applications needed and so the number of vaginal examinations.
This review set out to determine the effectiveness and safety of vaginal prostaglandins for third trimester cervical ripening and induction of labour in comparison with placebo or no treatment, or other vaginal prostaglandins (except misoprostol). We identified 63 randomised controlled studies involving a total of 10,441 women. Vaginal prostaglandin E2 is an effective induction agent as it increases the likelihood of vaginal birth within 24 hours with no evidence of an effect on the rate of caesarean section. Requirements for oxytocin augmentation were reduced. Prostaglandin E2 tablets, gels, or pessaries appear to be as effective as each other. Sustained release inserts were associated with a reduction in instrumental vaginal deliveries compared to vaginal PGE2 gel or tablet, an effect that was greater in women with an unfavourable cervix. Comparing vaginal prostaglandin E2 to placebo or no treatment, the risk of uterine hyperstimulation with fetal heart rate changes was increased. Sustained release pessaries were associated with trends of increased hyperstimulation, with and without fetal heart rate changes, compared to gel or tablets. Lower dose regimens, as defined in the review, appear as efficacious as higher dose regimens.
Very limited data were available in the included trials on time in labour and patient satisfaction. Few studies have addressed issues relating to the safety of using vaginal prostaglandins for induction of labour as an outpatient.
