A network meta-analysis «»? 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 |
In a multicentre RCT «de Vaan MD, Ten Eikelder ML, Jozwiak M et al. Mechanical methods for induction of labour. Cochrane Database Syst Rev 2019;10():CD001233. »1 824 women with a term singleton pregnancy in cephalic presentation, intact membranes, an unfavourable cervix, an indication for induction of labour, and no prior caesarean section were randomly allocated to induction of labour with a Foley catheter (n=412) or vaginal prostaglandin E2 (PGE2) gel (n=412). Because of the nature of the intervention the study was not blinded. Caesarean section rates were similar in the two groups (23% vs 20%, RR 1.13, 95% CI 0.87 to1.47, n=819). Two serious maternal adverse events were recorded, both in the prostaglandin group: one uterine perforation and one uterine rupture. In a meta-analysis including the trial above the caesarean section rate showed no difference between Foley catheter group and PGE2 group (RR 1.02, 95% CI 0.80 to 1.30; 3 trials, n=1431). There was a trend favouring the Foley catheter compared with prostaglandin in uterine hyperstimulation (10 vs 23; RR 0.44, 95% CI 0.21 to 0.91; 3 trials, n=1431, p=0.03) and in post-partum haemorrhage (31 vs 50; RR 0.60, 95% CI 0.37 to 0.95; 3 trials, n=1042, p=0.03).
A Cochrane review «Mechanical methods for induction of labour»? « de Vaan MD, Ten Eikelder ML, Jozwiak M et al. Mechanical methods for induction of labour. Cochrane Database Syst Rev 2023;3(3):CD001233. »2 included 112 trials involving a total of 22 055 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.