Safety/Efficacy Study Comparing the Misoprostol Vaginal Insert to Cervidil for Cervical Ripening and Induction of Labor

Induction of labor is required in approximately 20% of pregnant women. Although contractions can be brought on by oxytocin ("pitocin"), some women need help in softening the cervix, or mouth of the womb (uterus), before oxytocin can be started. Prostaglandins have been shown to ripen, or soften, the cervix; at present, the only prostaglandin approved for marketing by FDA for this purpose is dinoprostone. Dinoprostone can be delivered in several ways; one method is to use a polymer vaginal insert that slowly releases the dinoprostone directly to the cervical tissues. This product is called Cervidil (R) and has been marketed for more than 10 years in the United States. Misoprostol is another form of prostaglandin that is approved for protecting the stomach and intestinal lining for patients taking NSAIDs. Misoprostol has also been used by many obstetricians for cervical ripening and inducing contractions, but, it is not approved by FDA for this purpose. The same company that makes the Cervidil polymer insert has made an insert that will slowly release misoprostol. This study will determine whether this investigational insert containing misoprostol will decrease time to vaginal delivery compared to Cervidil. Two different doses of misoprostol will be tested (50 micrograms and 100 micrograms); each vaginal insert will gradually release a small, controlled amount of misoprostol over up to 24 hours. Comparator: The Cervidil (R) vaginal insert containing dinoprostone will be the comparator in this study.