Objective: Data supports shorter time to delivery with 60cc vs. 30cc Foley inflation for labor induction. Similarly, combination cervical ripening has a shorter time to delivery compared to single-agents. To date, no study has evaluated incremental benefit of higher Foley volume in the setting of combination ripening methods. Study Design: This is a secondary analysis of a prospective cohort study evaluating standardized induction management at 2 sites. Any cervical ripening method could be used. Site#1 used 60cc Foley inflation, while Site#2 used 30cc. For this analysis, patients were included if they underwent a term (≥37 week) induction from 2020-2022 with a singleton, intact membranes, and received combination methods of Foley and another agent. 1:1 propensity score matching balanced baseline parameters. Results: Of 4295 inductions, 2117 (49.3%) utilized combination cervical ripening methods. After propensity score matching, 1480 were included. Even in the context of combined ripening and standardized induction, Foley inflation to 60cc was associated with a 3-hour shorter labor length than 30cc (14.6h 10.4-21.3 v. 17.7h 12.4-24.4, p< 0.001). When censored for cesarean, patients who received 60cc Foley inflation delivered 70% faster than those who received 30cc (Hazard Ratio (HR) 1.731.36-2.21). There was no difference in cesarean, maternal morbidity, or neonatal morbidity. Conclusion: Even when using combined cervical ripening methods, 60cc Foley inflation is associated with reduced time to delivery as compared to 30cc without increasing morbidity.
Hamm et al. (Thu,) studied this question.