A network meta-analysis «Alfirevic Z, Keeney E, Dowswell T et al. Which met...»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 «Interventions for failure to achieve vaginal delivery within 24 hours ...»1). 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 |
A network meta-analysis «...»3 included 106 RCTs assessing 13 induction of labour methods among 30348 women. There was no clear evidence that any of the methods were more effective than vaginal misoprostol for the outcomes of failure to achieve vaginal delivery within 24 hours (see table «Failure to achieve vaginal delivery within 24 hours compared with vaginal misoprostol (≤ 50 μg)...»2), caesarean section due to non-reassuring fetal status, and perinatal death.
| Method | Direct evidence RR (95% CI) Certainty | Network evidence RR (95% CI) Certainty | Risk with control (vaginal misoprostol ≤ 50 μg) Network evidence | Risk with intervention Network evidence |
|---|---|---|---|---|
| Oral misoprostol (≤ 50 μg) | 1.32 (1.00 to 1.74) Moderate | 1.26 (1.08 to 1.48) High | 379 per 1000 | 478 per 1000 (409 to 561) |
| Sublingual or buccal misoprostol (≤ 50 μg) | 1.11 (0.93 to1.33) High | 1.04 (0.85 to 1.26) High | 379 per 1000 | 394 per 1000 (322 to 478) |
| Vaginal dinoprostone | 1.19 (0.99,1.44) Low | 1.20 (1.02 to 1.41) Low | 379 per 1000 | 455 per 1000 (387 to 534) |
| Oxytocin (alone) | 2.07 (1.27 to 3.37) Low | 2.03 (1.41 to 2.91) Low | 379 per 1000 | 769 per 1000 (534 to 1000) |
| Balloon catheters | 0.92 (0.68 to 1.24) Moderate | 1.43 (1.17 to 1.75) Low | 379 per 1000 | 542 per 1000 (443 to 663) |
| Oxytocin plus amniotomy | Not estimable | 0.41 (0.14 to 1.24) Moderate | 379 per 1000 | 155 per 1000 (53 to 470) |
| Balloon plus oxytocin | 0.94 (0.6 to 1.30) Low | 0.94 (0.71 to 1.26) Low | 379 per 1000 | 356 per 1000 (269 to 478) |
| Balloon plus misoprostol (≤ 50 μg) | 0.77 (0.55 to 1.06) High | 0.85 (0.60 to 1.19) High | 379 per 1000 | 322 per 1000 (227 to 451) |
A Cochrane review «Mechanical methods for induction of labour»1 «de Vaan MD, Ten Eikelder ML, Jozwiak M et al. Mec...»1 included 112 trials involving a total of 22055 women. The overall number of women not delivered within 24 hours did not differ significantly between balloon catheter (Foley or Atad) compared with vaginal PGE2 (RR 1.01, 95% CI 0.82 to 1.26; 7 trials; n=1685; I² = 79%). The risk of caesarean section was similar between groups (RR 1.00, 95% CI 0.92 to 1.09; 28 trials; n=6619). With balloon catheter versus vaginal PGE2 risk was lower for hyperstimulation (RR 0.35, 95% CI 0.18 to 0.67; 6 trials; n=1966) and for serious neonatal morbidity or perinatal death (RR 0.48, 95% CI 0.25 to 0.93; 8 trials; n=2757). Balloon versus low-dose vaginal misoprostol: it was uncertain whether there is a difference in vaginal deliveries not achieved within 24 hours (RR 1.09, 95% CI 0.85 to 1.39; 2 trials, n=340). A balloon catheter vs misoprostol probably reduces the risk of uterine hyperstimulation (RR 0.39, 95% CI 0.18 to 0.85; 8 trials, n=1322) but may increase the risk of a caesarean section (average RR 1.28, 95% CI 1.02 to 1.60; 12 trials, n=1756). Balloon versus low-dose oral misoprostol: a balloon catheter probably increases the risk of a vaginal delivery not achieved within 24 hours (RR 1.28, 95% CI 1.13 to 1.46; 2 trials, n=782) and probably slightly increases the risk of a caesarean section (RR 1.17, 95% CI 1.04 to 1.32; 7 trials, n=3178) when compared to oral misoprostol.