Applying Tension to the Transcervical Foley Balloon and Delivery Times in Term Nulliparous Women Undergoing Induction of Labor: A Randomized Controlled Trial.

OBJECTIVE:To investigate the effects of applying tension to a transcervical Foley balloon on delivery time in term nulliparous patients undergoing labor induction. METHODS:This cluster randomized clinical trial included 279 term nulliparous women presenting for labor induction with a plan for cervical ripening through transcervical Foley balloon placement. Participants were assigned to either the tension group (n=138) or the no-tension group (n=141) on the basis of randomized, weekly clusters (26 total clusters). The primary outcome measured was the time from initial Foley balloon insertion to delivery. Secondary outcomes included cesarean delivery rates, peripartum infection, and neonatal intensive care unit (NICU) admission. Our prior data suggested that delivery time in the tension group would be about 1,053 minutes. We estimated a sample size of 260 (130 per group, 26 clusters) on the basis of a 25% difference, power of 80%, and two-sided α of 0.05. RESULTS:A total of 279 term nulliparous patients were included in the analysis. The median time from Foley placement to delivery was 1,596 minutes (range 430-3,438 minutes) for the tension group and 1,621 minutes (range 488-3,323 minutes) for the no-tension group (P=.8); similar results were noted for time to vaginal delivery. No significant differences were observed in the secondary outcomes, including the rates of cesarean delivery (34.1% vs 29.8%, P=.7), peripartum infection, and NICU admission, between the two groups. CONCLUSION:Applying tension to a transcervical Foley balloon in term nulliparous women undergoing labor induction did not significantly reduce delivery time or improve secondary outcomes. CLINICAL TRIAL REGISTRATION:ClinicalTrials.gov, NCT05404776.