A network meta-analysis 3 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) (table T1). 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.
| Active intervention vs placebo | Odds ratio | 95% CI |
|---|---|---|
| i.v. oxytocin with amniotomy | 0.05 | 0.07 to 0.32 |
| Vaginal misoprostol ≥ 50 μg | 0.09 | 0.06 to 0.24 |
| Titrated (low-dose) oral misoprostol solution | 0.10 | 0.07 to 0.29 |
| Vaginal misoprostol < 50 μg | 0.11 | 0.09 to 0.32 |
| Buccal/sublingual misoprostol | 0.11 | 0.05 to 0.19 |
| Vaginal PGE2 pessary (normal release) | 0.11 | 0.04 to 0.16 |
| Oral misoprostol tablet ≥ 50 μg | 0.16 | 0.05 to 0.20 |
| Double-balloon or Cook's catheter | 0.18 | 0.01 to 0.16 |
| Foley catheter | 0.19 | 0.09 to 0.46 |
| Mifepristone | 0.76 | 0.05 to 0.20 |
A Cochrane review [Abstract] 1 included 10 trials with a total of 1 108 women. Mifepristone treated women were more likely to be in labour or to have a favourable cervix within 48 and 96 hours of treatment than were placebo treated/no treatment women (48 hours: RR 2.41, 95% CI 1.70 to 3.42, 4 studies, n= 293; 96 hours: RR 3.40, 95% CI 1.96 to 5.92, 2 studies, n=144). They were less likely to need augmentation with oxytocin (RR 0.80, 95% CI 0.66 to 0.97; 5 studies, n=499). Mifepristone treated women were less likely to undergo caesarean section (RR 0.74, 95% CI 0.60 to 0.92; 9 studies, n=1 043), but more likely to have an instrumental delivery (RR 1.43, 95% CI 1.04 to 1.96; 7 studies, n=814). Women receiving mifepristone were less likely to undergo a caesarean section as a result of failure to induce labour (RR 0.40, 95% CI 0.20 to 0.80). Abnormal fetal heart rate patterns were more common after mifepristone treatment (RR 1.85, 95% CI 1.17 to 2.93), but there was no evidence of differences in other neonatal outcomes. There is insufficient information on the occurrence of uterine rupture/dehiscence in the reviewed studies.
Another Cochrane review [Abstract] 2 interventions for labour induction in outpatient settings. Women who received mifepristone were less likely to require additional induction agents (average RR 0.59, 95% CI 0.37 to 0.95; 4 studies; n=311, I²=74%).
Comment: The quality of evidence is downgraded by imprecise results (few patients and wide confidence intervals).
Primary/Secondary Keywords