A Cochrane review [Abstract] 1 included 121 studies. Compared to placebo, misoprostol (a prostaglandin E1 analogue) was associated with reduced failure to achieve vaginal delivery within 24 hours (RR 0.51, 95% CI 0.37 to 0.71). Uterine hyperstimulation, without fetal heart rate changes, was increased (RR 3.52, 95% CI 1.78 to 6.99). Compared with vaginal prostaglandin E2, intracervical prostaglandin E2 and oxytocin, vaginal misoprostol was associated with less epidural analgesia use, fewer failures to achieve vaginal delivery within 24 hours and more uterine hyperstimulation. Compared with vaginal or intracervical prostaglandin E2, oxytocin augmentation was less common with misoprostol and meconium-stained liquor more common. Lower doses of misoprostol compared to higher doses were associated with more need for oxytocin augmentation and less uterine hyperstimulation, with and without fetal heart rate changes. No information on women's views was found.
A network meta-analysis 2 assessed the relative effectiveness, safety and cost-effectiveness of labour induction methods. 611 trials were included. The interventions most likely to achieve vaginal delivery within 24 hours were intravenous oxytocin with amniotomy (posterior rank 2; 95% credible intervals (CI) 1 to 9) and higher-dose (≥ 50 µg) vaginal misoprostol (rank 3; 95% CI 1 to 6). Odds ratios (and 95% CI) for failure to achieve vaginal delivery within 24 hours compared with placebo were 0.05 (0.07 to 0.32) for i.v. oxytocin with amniotomy; 0.09 (0.06 to 0.24) for vaginal misoprostol ≥ 50 μg; 0.10 (0.07 to 0.29) for titrated (low-dose) oral misoprostol solution; 0.11 (0.09 to 0.32) for vaginal misoprostol < 50 μg; 0.11 (0.05 to 0.19) for buccal/sublingual misoprostol; 0.18 (0.01 to 0.16) for double-balloon or Cook's catheter; 0.19 (0.09 to 0.46) for Foley catheter. Compared with placebo, several treatments reduced the odds of caesarean section, but there were considerable uncertainty in treatment rankings. For uterine hyperstimulation, double-balloon catheter had the highest probability of being among the best 3 treatments, whereas vaginal misoprostol (≥ 50 µg) was most likely to increase the odds of excessive uterine activity.
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