A randomised comparison of early versus late amniotomy following cervical ripening with a Foley catheter

Objectives Ripening of the cervix with a Foley catheter commonly results in cervical dilatation without contractions. We examined the outcome of labour in women who underwent induction of labour using a Foley catheter, followed by either 1. early amniotomy, or 2. augmentation of labour by oxytocin and late amniotomy. Design Prospective randomised clinical trial. Setting Labour and delivery ward of a university teaching hospital. Participants Pregnant women greater than or equal to38 weeks of a singleton gestation, who had had no prior caesarean section. Methods All women underwent cervical ripening using a Foley catheter. Following removal of the catheter, women were randomly assigned to either early (n = 80) or late amniotomy (n = 88). Main outcome measures Comparison of mode of delivery and duration of labour between the two groups. Results The rate of caesarean section was significantly higher in the early amniotomy group compared with the late amniotomy group (25% vs 7.9%; relative risk 1.74; 95% CI 1.3-2.34). The increase in caesarean section rate was due primarily to dystocia (15% vs 3.3%; relative risk 1.8; 95% CI 1.32-2.45). When excluding caesarean deliveries, no significant difference was found in duration of labour between the groups (8.3 hours (3.8) vs 7.7 hours (2.9)). Conclusions In women oxytocin followed by dystocia. who undergo cervical ripening with a Foley catheter, augmentation of labour by amniotomy during active labour results in a lower rate of caesarean delivery for dystocia.