Foley Bulb With Oral Misoprostol Versus Oral Misoprostol for Induction of Labor: A Cluster Randomized Trial

The purpose of this study is to determine whether the use of a transcervical foley catheter, in combination with the standard oral misoprostol regimen will result in a decreased primary cesarean delivery rate among women with a cervical dilation of 2 centimeters of less who require induction of labor at term. This study is not an FDA-regulated study: there is no intent to test the foley bulb under an FDA-regulated protocol. Likewise, there is no intent to submit the results of this study for a change in the labeling of the foley used for this study. This study was approved by the Institutional Review Board of the University of Texas Southwestern Medical Center, and by the Office of Research Administration at Parkland Health and Hospital System.

This will be a prospective, cluster-randomized trial comparing two accepted methods of induction of labor at term among women who present for delivery at Parkland Hospital. Eligible participants will include nulliparous and multiparous women at 37 weeks gestation or greater, with a living, singleton fetus and no major fetal malformations, in cephalic presentation, with intact membranes, no prior uterine scar, who qualify for prostaglandin administration and who have a cervical dilation of 2 centimeters or less, measured at the level of the internal os. Patients with latex allergy, non-reassuring fetal status, HIV, active herpes outbreak, a prior uterine scar, or any contraindication to prostaglandins (including 4 or more painful contractions per 10 minutes prior to prostaglandin administration) will be excluded from participation in the study.

Computer-generated cluster randomization will occur on a weekly basis for all study participants, to either the combination method of foley bulb plus oral misoprostol regimen (study group) or to oral misoprostol alone regimen (control).

According to the randomization protocol each week, participants will be randomized to either the standard of care (oral misoprostol/control group) or standard of care plus foley bulb (study group). The study group will undergo placement of a 30 French foley catheter filled with 30-35cc sterile saline into the cervix in addition to the standard regimen of oral misoprostol 100 micrograms given every 4 hours for a maximum of 2 doses, for patients who meet criteria for fetal well-being, and do not had more than 4 painful contractions in 10 minutes. Misoprostol will not be administered to patients who have progressed to active labor, defined as 4 centimeters cervical dilation. The control group will undergo induction with our current standard oral misoprostol protocol alone, administered as 100 micrograms given every 4 hours for a maximum of 2 doses. Both groups will receive oxytocin as indicated by current labor protocols at our institution.

The primary outcome will be the rate of vaginal delivery. Secondary outcomes will include obstetric outcomes, maternal outcomes, and neonatal outcomes. Obstetric outcomes will include indication for induction, need for oxytocin, indication for cesarean delivery, time to active labor, time to delivery, labor analgesia, presence of chorioamnionitis, meconium-stained amniotic fluid, terbutaline use, tachysystole (defined as 6 or more contractions in 10 minutes or tetanic contraction of 120 seconds or longer) or hyperstimulation syndrome (defined as tachysystole accompanied by fetal heart rate decelerations). Maternal outcomes will include estimated blood loss, transfusion requirement, postpartum fever, uterine rupture, and unplanned hysterectomy. Neonatal outcomes will include umbilical cord blood pH, 5-minute APGAR score, intubation or ventilation in the delivery room, neonatal sepsis, and admission to Neonatal Intensive Care Unit (NICU) admission.