A Cochrane review [Abstract] 1 included 17 trials involving 2 566 women. In a single study of 100 women amniotomy and intravenous oxytocin resulted in fewer women being undelivered vaginally at 24 hours than amniotomy alone (RR 0.03, 95% CI 0.001-0.49). Amniotomy and intravenous oxytocin resulted in significantly fewer instrumental vaginal deliveries than placebo (RR 0.18, 95% CI 0.05-0.58). In two studies comparing amniotomy and oxytocin with vaginal PGs (amniotomy or oxytocin was added to PGs in case of no spontaneous labour) there were more postpartum haemorrhage (13.75% vs 2.5%, RR 5.5, 95% CI 1.26-24.07, 160 women).
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) (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 |
| Oral misoprostol tablet < 50 μg | 0.22 | 0.07 to 0.39 |
Comment: The quality of evidence is downgraded by imprecise results (limited study size for each comparison) and by indirectness (no single study addressed all the primary outcomes).
Primary/Secondary Keywords