Sustained-release dinoprostone vaginal pessary with concurrent high-dose oxytocin infusion compared to sustained-release dinoprostone vaginal pessary followed 6 h later by high-dose oxytocin infusion for labor induction in women at term with unfavorable cervix: a randomized controlled trial.

Objective: To compare the efficacy and safety of sustained-release dinoprostone vaginal pessary and concurrent high-dose oxytocin infusion with sustained-release dinoprostone vaginal pessary followed 6 h later by high-dose oxytocin infusion for cervical ripening and labor induction.

Methods: A total of 500 nulliparous or multiparous women with a singleton pregnancy, Bishop score ≤4 and admitted for labor induction. Women were randomly assigned to induction of labor using intravaginal dinoprostone with concurrent high-dose oxytocin (n = 250) or intravaginal dinoprostone pessary followed 6 h later by high-dose oxytocin (n = 250). The primary outcome was the number of vaginal deliveries achieved within 24 h of labor induction.

Results: Baseline characteristics of both groups were comparable. Vaginal delivery within 24 h of labor induction was significantly increased with sustained-release dinoprostone followed 6 h later by high-dose oxytocin infusion (92.8 vs. 82.0%, RR 2.82, 95% CI 1.58-5.04). There were more cesarean section deliveries in the dinoprostone with concurrent high-dose oxytocin group (16.8 vs. 6.8%, RR 0.36, 95% CI 0.20-0.65). Maternal outcomes did not differ significantly. An Apgar score of <7 at 5 min was found more often in the dinoprostone with concurrent high-dose oxytocin group (3.6%) in comparison to dinoprostone pessary followed 6 h later by high-dose oxytocin (0.8%), although this was not statistically different (RR 0.21, 95% CI 0.04-1.01).

Conclusion: Sustained-release dinoprostone followed 6 h later by high-dose oxytocin infusion appears to be safer and more effective than sustained-release dinoprostone with concurrent high-dose oxytocin infusion in achieving cervical ripening and successful vaginal delivery.