Oral prostaglandin E2 for induction of labour

This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology.

To determine the effects of oral prostaglandin E2 for third trimester induction of labour.

The Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register and bibliographies of relevant papers. Date of last search: December 2000.

The criteria for inclusion included the following: (1) clinical trials comparing oral prostaglandin E2 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; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions.

A strategy has been developed to deal with the large volume and complexity of trial data relating to labour induction. This involves a two-stage method of data extraction. The initial data extraction is done centrally, and incorporated into a series of primary reviews arranged by methods of induction of labour, following a standardised methodology. The data will then be extracted from the primary reviews into a series of secondary reviews, arranged by category of woman. To avoid duplication of data in the primary reviews, the labour induction methods have been listed in a specific order, from one to 25. Each primary review includes comparisons between one of the methods (from two to 25) with only those methods above it on the list.

There were 19 studies included in the review. Of these 15 included a comparison using either oral or intravenous oxytocin with or without amniotomy. The quality of studies reviewed was not high. Only seven studies had clearly described allocation concealment. Only two studies stated that providers and/or participants were blinded to treatment group. For the outcome of vaginal delivery not achieved within 24 hours, in the composite comparison of oral PGE2 versus all oxytocin treatments (oral and intravenous, with and without amniotomy), there was a trend favoring oxytocin treatments (relative risk (RR) 1.97, 95% confidence interval (CI) 0.86 to 4.48). For the outcome of cesarean section, in the comparison of PGE2 versus no treatment or placebo, PGE2 was favored (relative risk (RR) 0.54, 95% confidence interval (CI) 0.29,0.98). Otherwise, there were no significant differences between groups for this outcome. Oral prostaglandin was associated with vomiting across all comparison groups.

Oral prostaglandin consistently resulted in more frequent gastrointestinal side effects, in particular vomiting, compared with the other treatments included in this review. There were no clear advantages to oral prostaglandin over other methods of induction of labour.