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

Official title

Comparison of the Effectiveness of Labor Induction Using Dinoprostone Followed by Oxytocin Versus Oxytocin Alone in Term Pregnancies With Premature Rupture of Membranes and an Unfavorable Cervix - A Randomized Clinical Trial

Overview

This study is being done to learn more about the best way to start labor for pregnant women whose water breaks at term before labor begins, a condition called term prelabor rupture of membranes (term PROM). When this happens and the cervix is not ready for labor, it is unclear which induction method works best and is safest for mother and baby. The purpose of this study is to compare two common ways to induce labor in women with term PROM and an unfavorable cervix (Bishop score ≤ 6). One group will receive a vaginal dinoprostone insert (Propess) for 6 hours to soften the cervix, followed by oxytocin if labor does not start. The other group will receive immediate oxytocin through a vein. Pregnant women aged 18 years or older with a single baby in head-down position at 37-42 weeks, whose water has broken and whose cervix is not yet favorable, may be able to join this study. All care will be provided at the National Hospital of Obstetrics and Gynecology in Hanoi, Vietnam, where both medicines are already used in routine practice. The main outcome is how many women have a vaginal birth. The study will also look at how long it takes from induction to birth, complications for mothers and babies, and women's experiences of labor. The results may help doctors choose the safest and most effective way to induce labor for women with term PROM in the future.

Detailed description

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.

Interventions

• Drug Sequential Induction: Dinoprostone Followed by Oxytocin
  A sequential induction strategy in which a 10-mg vaginal dinoprostone insert (Propess) is placed for cervical ripening. After 6 hours, if active labor has not begun or uterine contractions are inadequate, intravenous oxytocin is initiated according to the hospital's standardized induction protocol. Continuous fetal monitoring is applied, and tachysystole is managed per institutional guidelines.
• Drug Immediate Oxytocin Induction
  Intravenous oxytocin is used for immediate induction of labor in women with term prelabor rupture of membranes and an unfavorable cervix. Oxytocin is started according to the hospital's standardized induction protocol without prior use of cervical ripening agents. Maternal and fetal status are monitored throughout labor, and uterine tachysystole is managed according to institutional guidelines.

Primary outcome measures

• Vaginal delivery [Time frame: From induction until delivery, assessed up to 36 hours after randomization]

Secondary outcome measures (12)

• Mode of delivery [Time frame: Within 24 hours from labor induction]
• Time from induction of labor to delivery [Time frame: From induction until delivery, assessed up to 24 hours after induction]
• Oxytocin augmentation [Time frame: From induction until delivery, assessed up to 24 hours after induction]
• Uterine hyperstimulation [Time frame: From induction until delivery, assessed up to 24 hours after induction]
• Maternal satisfaction [Time frame: Once between 90 minutes and 3 hours after delivery]
• Haemorrhage [Time frame: Within 24 hours from delivery]
• Uterine rupture [Time frame: From randomization until maternal hospital discharge, assessed up to 28 days after randomization]
• Hysterectomy for any complications resulting from birth [Time frame: From delivery until maternal hospital discharge, assessed up to 28 days after delivery]
• Maternal infection [Time frame: From induction until maternal hospital discharge, assessed up to 28 days after induction]
• Damage to internal organs [Time frame: From delivery until maternal hospital discharge, assessed up to 28 days after delivery]
• Intensive care admission [Time frame: From randomization until maternal hospital discharge, assessed up to 28 days after randomization]
• Cardiorespiratory arrest [Time frame: From randomization until maternal hospital discharge, assessed up to 28 days after randomization]

Eligibility criteria

Inclusion criteria

• Maternal age ≥ 18 years
• Gestational age from 37 to 42 weeks, determined by last menstrual period or by a first- or second-trimester ultrasound
• Live singleton fetus
• Prelabor rupture of membranes (PROM) confirmed by at least one of the following:

• Amniotic fluid visibly draining from the cervical os during sterile speculum examination
• Pool of fluid in the posterior fornix
• Cephalic presentation
• Bishop score ≤ 6
• No spontaneous uterine contractions
• No contraindications for vaginal delivery

Exclusion criteria

• Active labor
• Previous uterine surgery (e.g., cesarean section)
• Chorioamnionitis or non-reassuring fetal status
• Major fetal anomalies
• Contraindications to prostaglandin or vaginal delivery
• Refusal to participate

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Open label

Primary purpose

Treatment

Study locations

Vietnam · 1 center

• National Hospital of Obstetrics and Gynecology — Hanoi

Publications

• Prelabor Rupture of Membranes: ACOG Practice Bulletin, Number 217. Obstet Gynecol. 2020 Mar;135(3):e80-e97. doi: 10.1097/AOG.0000000000003700. PMID 32080050
• National Institute for Health and Care Excellence (NICE). Inducing labour. NICE guideline [NG207]. London: NICE; 2021. Available from: https://www.nice.org.uk/guidance/ng207
• Kunt C, Kanat-Pektas M, Gungor AN, Kurt RK, Ozat M, Gulerman C, Gungor T, Mollamahmutoglu L. Randomized trial of vaginal prostaglandin E2 versus oxytocin for labor induction in term premature rupture of membranes. Taiwan J Obstet Gynecol. 2010 Mar;49(1):57-61. doi: 10.1016/S1028-4559(10)60010-1. PMID 20466294
• Gungorduk K, Asicioglu O, Besimoglu B, Gungorduk OC, Yildirm G, Ark C, Sahbaz A. Labor induction in term premature rupture of membranes: comparison between oxytocin and dinoprostone followed 6 hours later by oxytocin. Am J Obstet Gynecol. 2012 Jan;206(1):60.e1-8. doi: 10.1016/j.ajog.2011.07.035. Epub 2011 Jul 30. PMID 21924396
• Gulersen M, Zottola C, Li X, Krantz D, DiSturco M, Bornstein E. Chorioamnionitis after premature rupture of membranes in nulliparas undergoing labor induction: prostaglandin E2 vs. oxytocin. J Perinat Med. 2021 Jun 9;49(9):1058-1063. doi: 10.1515/jpm-2021-0094. Print 2021 Nov 25. PMID 34109770
• Mackeen AD, Durie DE, Lin M, Huls CK, Qureshey E, Paglia MJ, Sun H, Sciscione A. Foley Plus Oxytocin Compared With Oxytocin for Induction After Membrane Rupture: A Randomized Controlled Trial. Obstet Gynecol. 2018 Jan;131(1):4-11. doi: 10.1097/AOG.0000000000002374. PMID 29215519
• Borovac-Pinheiro A, Inversetti A, Di Simone N, Barnea ER; FIGO Childbirth and Postpartum Hemorrhage Committee. FIGO good practice recommendations for induced or spontaneous labor at term: Prep-for-Labor triage to minimize risks and maximize favorable outcomes. Int J Gynaecol Obstet. 2023 Oct;163 Suppl 2:51-56. doi: 10.1002/ijgo.15114. PMID 37807591
• Middleton P, Shepherd E, Flenady V, McBain RD, Crowther CA. Planned early birth versus expectant management (waiting) for prelabour rupture of membranes at term (37 weeks or more). Cochrane Database Syst Rev. 2017 Jan 4;1(1):CD005302. doi: 10.1002/14651858.CD005302.pub3. PMID 28050900

Identifiers

NCT: NCT07366359 · NHOG.2025.POXY-PROM

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗