Tension Versus Tension- Free Foley Balloon for Cervical Ripening

Tension Versus Tension-Free Foley Balloon for Cervical Ripening in Nulliparous Women Undergoing Induction of Labor: A Cluster Randomized Controlled Trial

Foley balloons are commonly used as a mechanical method of cervical ripening for induction of labor. Foley balloons may be placed either under tension or without tension (tension-free). The purpose of our study is to examine time to delivery in nulliparous women undergoing induction of labor who have a Foley balloon placed as a mechanical cervical dilator, assigned to either tension or without tension. The goal is to determine if there is a potential added benefit to placing the Foley balloon on tension as compared to no tension. Our hypothesis is that Foley balloon under tension for cervical ripening results in shorter time to vaginal delivery compared to Foley balloon placed without tension.

This is a pragmatic cluster randomized clinical trial. The target population is nulliparous women who present for induction of labor at term. If there is a decision by the obstetric team to place a transcervical Foley dilator for cervical ripening in a prospective subject meeting inclusion criteria for the study, the obstetric provider will follow the weekly randomization sequence for study group (No Tension) or the control group (Tension) based on the assigned cluster for the entire unit for that week. Both study groups will receive standardized labor management as Foley balloon placed with tension and without tension are both considered standard of care at our institution.

The Tension standard of care (control group) will undergo induction of labor by placement of a transcervical Foley balloon, which is standard of care at our institution. The balloon tubing will be pulled to create tension and will then be taped to the patient's inner thigh.

The No Tension standard of care (study group) will undergo induction of labor by placement of a transcervical Foley balloon. The balloon tubing will be left free of tension and will hang freely.

Subjects in the control and study group will then undergo standard intrapartum care. The total participation time in the study will be considered terminated following delivery.

Inclusion Criteria:

• Term induction of labor
• Nulliparous
• Vertex
• Singleton
• Plan for Foley balloon placement by the managing obstetrics team
• Cervical exam less than 3 cm dilated and less than or equal to 60% effaced

Exclusion Criteria:

• Patient unwilling or unable to provide verbal consent
• Fetal demise or major congenital anomaly
• Preterm (<37 0/7weeks)
• Multiple gestation
• Previous uterine surgery
• Abnormal placentation
• Malpresentation
• Magnesium infusion for preeclampsia with severe features
• Prelabor rupture of membranes
• Fetal growth restriction
• Non-reassuring fetal heart rate tracing prior to inclusion