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 ≥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