A Randomized Controlled Study Comparing Cervical Foley Catheter, Vaginal Dinoprostone and a Combination of the Two Methods for Induction of Labor

Introduction:

Labor induction, an iatrogenic initiation of labor is one of the most common obstetric procedures performed nowadays. The rate of induction of labor more than doubled from 1990 through 2010 from 9.6% to 23.8% in the United State alone. There are many methods to promote labor induction, including mechanical and pharmacological methods that can be used alone or in conjugation. Choosing the right method for the right patient can be challenging, and up until now there is limited information regarding the most suitable and effective approach for cervical ripening and labor induction. Out of the vast options for cervical ripening, the Foley catheter and vaginal prostaglandins are frequently used. To date, few clinical trials have compared the different methods to evaluate the effectiveness and the risk in each method. Two randomized controlled trials compared the Foley catheter method with the vaginal dinoprostone method. In one study, the Foley catheter was found to be superior to the vaginal dinoprostone with regards to time to delivery, whereas in the other study no difference was found. In an additional trial, Foley bulb with vaginal Misoprostol was compared to Misoprostol alone. The first treatment resulted in a shorter time to delivery. These finding did not correlate with previous trials that either found no difference or superiority to Misoprostol alone. A recent study comparing Foley catheter with PGE2 in term oligohydramnios pregnancies showed that time to delivery was shorter in the PGE2 group. A meta-analysis comparing Misoprostol with dinoprostone showed that the first is more effective, but the latter is safer. Since in some obstetrics conditions such as preeclampsia and Intrauterine growth restriction (IUGR) an expeditious induction of labor may be needed, a combination of methods may fasten the induction to delivery interval. A recent study presented as an oral presentation at the society of maternal fetal medicine a month ago used a combination of Foley catheter and prostaglandins to induce labor. They found that this arm had the shorter induction to delivery time and had no serious side effects.

In this study, The investigators intend to compare the mechanical (Foley catheter combined with Oxytocin) method, to a pharmacological one (dinoprostone-PGE2) and to a combination of the two methods in cervical ripening in an unfavorable cervix. The investigators will also examine if using the two methods in tandem will provide an additive effect.

The study will include 3 groups; in each group about 100 participants will be enrolled, which will be suited to the including and excluding criteria. The investigators have about 200 inductions per year of primigravida women. The investigators expect to enroll 300 participants in about 2 years' time.

On enrollment the patient will receive a number and will be assigned to one of the three groups. All the participants will be assigned to a 20 minute reassuring monitor before insertion the device.