DOuble-BAlloon Versus PROstaglandin E2 for Cervical Ripening in Low Risk Pregnancies

Induction of labor (IOL) is a technique to establish vaginal delivery when the risks for continuing the pregnancy for mother or baby are higher than the risks of delivery. In case the cervix is unripe, cervical ripening before the onset of labor is needed. The two main mechanisms of cervical ripening can be categorized as mechanical or pharmacological. A Cochrane systematic review and other recent meta-analysis have shown that cervical ripening with a balloon is probably as effective as induction of labor with vaginal Prostaglandin E2. However, this conclusion is based on low to moderate quality evidence. Only a limited number of randomized clinical trials (RCTs) have been conducted. Many of those suffering from small sample sizes and different study subjects, i.e. high-risk subjects only, and mixed population. In current practice, induction of labor is not only used in high-risk patients with clear indications for pregnancy termination. The ARRIVE trial has shown a significant benefit of labor induction over expectant management among the low-risk population. Based on this evidence, the American College of Obstetricians and Gynecologists (ACOG) has suggested: "It's time to induce of labor at 39th week of gestation". Since then, there is a trend in favoring elective induction before the due date over expectant management. Besides, more and more pregnant women want to shorten the duration of pregnancy or to time the birth of the baby due to the convenience of the mother and/or healthcare workers. This makes the optimal method of Induction of Labor in terms of effectiveness and safety for both mothers and their babies even more important. In this study, the investigators will compare the effectiveness and safety of double-balloon catheter and Prostaglandin E2 for elective labor induction in low-risk pregnancies.