Retrospective Comparison of PGE2 Vaginal Insert and Foley Catheter for Outpatient Cervical Ripening

Objective: To compare the efficacy of two methods of outpatient cervical ripening (CR): an intracervical Foley catheter and a prostaglandin E-2 (PGE)(2) slow-release vaginal insert. Methods: All records of women receiving outpatient CR at a tertiary care hospital from January 2017 to June 2018 were retrospectively reviewed. We compared time from insertion of first CR agent until delivery between groups using a Cox proportional hazards (CPH) model. Exclusion criteria included age <18 years, multiple gestation, or contraindication to either CR method. Secondary outcomes included time from removal of agent and time from admission until delivery, additional CR used, uterine tachysystole, labour and delivery complications, type of delivery, and adverse neonatal outcomes. Results: A total of 153 patients were included (82 Foley; 71 PGE(2)). Baseline characteristics were comparable except for lower dilation in the PGE(2) group (16% vs. 38% <1cm dilated; P < 0.05). In the CPH model, time from insertion to delivery was not different between PGE(2) and Foley catheter groups (median 27 vs. 33 h), controlling for parity, gestational age, initial dilation, and use of oxytocin (HR 1.13, 95% confidence interval 0.77-1.68). Patients in the PGE(2) group were more likely to experience uterine tachysystole (9% vs. 0%; P < 0.01) and require another method of CR (34% vs. 1%; P < 0.001). There were no differences in neonatal or maternal adverse outcomes between groups. Conclusion: Our results suggest that outpatient Foley catheter and PGE(2) CR are comparable in time from insertion to delivery; however, PGE(2) inserts are associated with higher rates of tachysystole and the need for second CR method. A prospective study is warranted to further investigate these findings.