Labor length differences in combination ripening with 60cc versus 30cc Foley inflation volume: a propensity score-matched study

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) 1.73[1.36-2.21]). 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.

Publication History

Received: 29 January 2026

Accepted: 16 February 2026

Accepted Manuscript online:
19 February 2026