Prostaglandins Versus Trans-cervical Balloon for Induction of Labor in Fetal Growth Restriction (PROBIN)

Fetal growth restriction (FGR) is associated with increased perinatal morbidity and mortality in late pregnancy. Because of this higher risk of adverse perinatal outcome, induction of labor is often proposed and require cervical ripening when the cervix is not favorable, i.e. Bishop score less than 6. Two methods of cervical ripening are currently available and used: pharmacological (prostaglandins) and mechanical (trans-cervical balloon). Growth-restricted fetuses are a population at increased risk for non-reassuring fetal status and hypoxia during labor because of their lower weight. Prostaglandins can lead to cardiotocograph (CTG) tracing abnormalities by causing uterine tachysystole in normal-weight fetuses. Nevertheless, the question of the method of induction of labor has been poorly studied in the population of growth-restricted fetuses. None of the national and international societies reports in their guidelines which method of induction of labor should be offered to pregnancies complicated by a fetal growth restriction. A few retrospective studies are in favor of an increased risk of uterine tachysystole with consequences on the CTG tracing in the case of cervical ripening with prostaglandins compared to the trans-cervical balloon. However, the results of these studies lack robustness due to important methodological limitations. Because trans-cervical balloon is a mechanical method of cervical ripening, it may be less likely to cause uterine tachysystole and thus fewer non-reassuring fetal status. Thus, the risk of cesarean section in labor could be decreased compared with the use of prostaglandins in the growth-restricted fetal population. To date, there is no published quality randomized controlled trials on the optimal method of cervical ripening in induction of labor for FGR fetuses. The present large-scale randomized trial aim to define the preferred method of induction for these fetuses, associated with a lower risk of cesarean delivery. If it is demonstrated that one method of induction (trans-cervical balloon) is superior to another (prostaglandins) in reducing the cesarean section rate, without increasing neonatal morbidity, the results of our study are likely to lead to changes in national and international recommendations.