PGE2 Followed by Oxytocin vs Oxytocin in Term PROM (POXY-PROM)

Prelabor rupture of membranes at term (term PROM) occurs in approximately 8% of pregnancies and is associated with increased risks of maternal infection, neonatal morbidity, and cesarean delivery when labor does not begin promptly. International guidelines recommend active induction of labor for women with term PROM; however, the optimal induction strategy for women presenting with an unfavorable cervix (Bishop score ≤ 6) remains uncertain. Oxytocin is widely used for induction of labor and is effective when the cervix is favorable, but its efficacy may be reduced in the presence of an unripe cervix. Prostaglandin E2 (dinoprostone) is commonly used for cervical ripening and may improve the likelihood of vaginal delivery when administered prior to oxytocin. Previous randomized trials comparing dinoprostone followed by oxytocin with oxytocin alone have suggested potential benefits, but the available evidence is limited by small sample sizes and inconsistent results. Additional high-quality randomized evidence is therefore required to guide clinical practice in this population. This randomized controlled trial compares two induction strategies for women with term PROM and an unfavorable cervix: (1) cervical ripening using a 6-hour vaginal dinoprostone (Propess) insert followed by intravenous oxytocin if labor has not commenced, and (2) immediate induction with intravenous oxytocin alone. Both interventions are routinely used in clinical practice in Vietnam and are considered safe. Participants are randomly assigned in a 1:1 ratio using a computer-generated randomization sequence with variable block sizes of 4 and 6, with allocation concealment ensured through centralized randomization. Randomization is performed after confirmation of eligibility and completion of the informed consent process. Participants remain in their assigned study arm throughout the trial, and no crossover between arms is permitted. All aspects of intrapartum care, including fetal heart rate monitoring, assessment of labor progress, and management of uterine tachysystole or other complications, are conducted according to standard institutional protocols. The primary outcome of the study is vaginal delivery. Secondary outcomes are selected in accordance with the internationally developed core outcome set for trials on induction of labour and include key maternal, neonatal, and patient-reported outcomes. Maternal outcomes include mode of delivery, time from induction to delivery, need for oxytocin augmentation, uterine hyperstimulation, postpartum hemorrhage, maternal infection, admission to intensive care, hysterectomy, and maternal death. Neonatal outcomes include Apgar scores, admission to the neonatal intensive care unit, neonatal infection, hypoxic-ischemic encephalopathy or need for therapeutic hypothermia, and neonatal death. Patient-reported outcomes, including overall labor pain and maternal satisfaction with the birth process, are also assessed. A total sample size of 450 participants has been calculated to provide adequate statistical power while accounting for potential attrition. The findings of this study are expected to clarify whether cervical ripening with dinoprostone prior to oxytocin induction improves clinically meaningful outcomes for women with term PROM and an unfavorable cervix, and may help inform future national and international guidelines on induction of labor.