Randomized Control Trial Comparing Hygroscopic Cervical Dilators to Cervical Ripening Balloon for Outpatient Cervical Ripening (CORC Trial).

BACKGROUND: Outpatient term pre-induction cervical ripening with mechanical agents has been associated with reduced length of stay, decreased cesarean delivery rates, low maternal and neonatal complications, and increased incidence of vaginal delivery within 24 hours.

OBJECTIVE(S): This study aims to demonstrate equivalent efficacy between synthetic hygroscopic dilators and the single balloon catheter for outpatient cervical ripening.

STUDY DESIGN: This randomized control equivalence trial compares synthetic hygroscopic dilators to the 30cc silicone single balloon catheter in primiparous and multiparous patients undergoing induction. The primary outcome was time from admission to delivery, with a prespecified 3-hour margin of equivalence. Secondary objectives were patient outcomes and perspectives.

RESULTS: Between March 1st , 2019, and May 31st , 2021, 1,605 patients met screening criteria and 174 completed the study. Mean admission-to-delivery time was equivalent at 18.01 hours for the dilator group versus 17.55 hours for the balloon group (p=0.04). The cesarean delivery rate of primiparous patients was similar at 28.1% with dilators versus 29.7% with balloon. The groups had similar median cervical dilation and pain scores on insertion and admission. Overall patient satisfaction was high, 92.8% with dilators versus 96.2% with balloon. The balloon group had significantly higher rates of early admission and device expulsion.

CONCLUSION(S): Although the enrollment goal was unmet, this study suggests outpatient cervical ripening with synthetic hygroscopic dilators and the single balloon catheter are both efficacious with similar time from admission to delivery, pain scores, and patient satisfaction with the procedure.