Concurrent oxytocin with dinoprostone pessary versus dinoprostone pessary in labour induction of nulliparas with an unfavourable cervix: a randomised placebo-controlled trial

Objective  To compare concurrent oxytocin with dinoprostone pessary versus dinoprostone pessary in labour induction for nulliparas with an unfavourable cervix.

Design  A randomised double-blind study.

Setting  University Malaya Medical Centre, Malaysia.

Population  Nulliparas at term with intact membranes, Bishop score ≤ 6 and admitted for labour induction.

Methods  All women received 3 mg dinoprostone pessary for labour induction. Those randomised to the oxytocin arm received oxytocin infusion started at 1 mu/minute and doubled every 30 minutes to a maximum 16 mu/minute. Women assigned to placebo received identical volume of saline infusion. After 6 hours, infusion was stopped and vaginal reassessment performed to guide further management.

Main outcome measures  Primary outcome was vaginal delivery within 24 hours.

Results  Concurrent oxytocin infusion with dinoprostone pessary did not significantly increase vaginal delivery rate within 24 hours (48.6 versus 35.9%; P= 0.07, relative risk [RR] 1.4 [95% CI 1.0–1.9]). It reduced the requirement for repeat dinoprostone (37.1 versus 61.2%; P= 0.001, RR 0.61 [95% CI 0.45–0.81]) and improved maternal satisfaction with the birth process (median score of 3 versus 5 on a 10-point visual analogue scale, P= 0.007). Caesarean rates were not different (41.9 versus 44.7%, P= 0.52).

Conclusions  Labour induction with concurrent oxytocin infusion and vaginal dinoprostone could be considered for nulliparas with an unfavourable cervix. Larger studies are needed.