Early Amniotomy Versus Delayed Amniotomy Following Foley Catheter Ripening in Nulliparous Labor Induction

Amniotomy (breaking the bag of water) is commonly used in the induction of labor. However, the timing is highly variable. The purpose of this study is to determine if first time mothers undergoing induction of labor with a Foley catheter experience a decrease in their labor time when undergoing early amniotomy (breaking the bag of water within 1 hour of Foley catheter removal) than when undergoing delayed amniotomy (breaking the bag of water at least 4 hours after Foley catheter removal). Other aims include the relationship between timing of amniotomy and cesarean section, postpartum hemorrhage, intrauterine infection, neonatal Apgar score \<7 at 5 minutes, neonatal need for intensive care. The investigators hypothesize that induction of labor with Foley catheters followed by early amniotomy will result in a decreased duration of labor compared to those who undergo delayed amniotomy.

This randomized clinical trial of consenting nulliparous women undergoing induction of labor with a Foley catheter seeks to determine whether use of early amniotomy (defined as amniotomy within 1 hour of Foley catheter removal) improves obstetrical outcomes when compared with delayed amniotomy (defined as amniotomy at least 4 hours following Foley catheter removal). This project will include 110 women recruited from the obstetrical service at Prentice Women's Hospital. Women will be included if they are at least 37 weeks gestation, have a singleton pregnancy, have intact membranes and are undergoing an induction of labor using a Foley catheter. Following removal of Foley catheter, women will be assessed for safety of amniotomy and if appropriate, randomized to either early amniotomy or delayed amniotomy. Women will be randomized with equal probability to the intervention group using block randomization stratified by use of Foley catheter alone or Foley catheter-misoprostol use. Women in the early amniotomy group will undergo amniotomy within 1 hour of Foley catheter removal. Women in the delayed amniotomy group will undergo amniotomy at least 4 hours following Foley removal. The remainder of labor management will be at the discretion of each woman's obstetric provider. Prior to discharge from the hospital, baseline demographic and clinical data will be obtained via chart review