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 > or =38 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 who undergo cervical ripening with a Foley catheter, augmentation of labour by oxytocin followed by amniotomy during active labour results in a lower rate of caesarean delivery for dystocia.