(810) The PROMMO (Prelabor Rupture of Membranes: Misoprostol vs Oxytocin) Study: A Randomized Control Trial

This is a non-blinded, block-randomized control trial in a single institution from 08/2020 to 05/2024. Patients were randomized to either oral MP or intravenous OT. Inclusion criteria included confirmed PROM, an unfavorable modified Bishop score (< 7), gestational age 34w0d and 41w6d, and ability to consent in Spanish or English. The primary outcome was time from first induction agent to vaginal delivery. Secondary outcomes included Cesarean delivery, IAI, and postpartum hemorrhage (PPH). Statistical analysis included chi-square or Fisher's exact tests and t-test or Wilcoxon-Rank Sum as appropriate.

Results:
We enrolled 134 of our planned 200 patients due to inability to recruit after the adoption of misoprostol as standard of care in our institution. MP patients received a median of 2 doses; 72% required oxytocin after ripening. Median time to oxytocin initiation in the MP group was 428 min [IQR 289,560]. Study arms did not differ in baseline characteristics. The difference in time from first induction agent to vaginal delivery between oral MP 637 min [IQR 457,1074.5] and OT 783 min [598,1275] was not significant (p=.208). There was, however, a significant difference in the length of the second stage (38 min [18.5, 91] MP vs 68 [29.5, 144.5] OT, p=0.034). There was no difference in immediate PPH (12.3% v. 5.8% p=0.233), Cesarean delivery (20% v. 24.6% p=0.689), IAI (1.5% vs 7.3% p=0.209), or NICU admission (24.6% v. 23.2% p=0.846) for MP vs OT, respectively.

Conclusion:

This study demonstrated a trend toward a shorter first stage and significantly shorter second stage of labor for patients with PROM treated with MP compared to OT. There was no difference in adverse outcomes such as PPH or IAI.  Oral misoprostol should be considered for labor induction in patients presenting with an unfavorable cervix and PROM.