Amniotomy plus intravenous oxytocin for induction of labour
A Cochrane review 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.
Table 1. Interventions for failure to achieve vaginal delivery within 24 hours
|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).
1. Howarth GR, Botha DJ. Amniotomy plus intravenous oxytocin for induction of labour. Cochrane Database Syst Rev 2001;(3):CD003250. [PMID:11687061]
2. Alfirevic Z, Keeney E, Dowswell T et al. Which method is best for the induction of labour? A systematic review, network meta-analysis and cost-effectiveness analysis. Health Technol Assess 2016;20(65):1-584. [PMID:27587290]
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