Transvaginal sonographic assessment of the cervix for prediction of successful induction of labor in nulliparous women

Abstract

Approximately 20% of parturients undergo induction of labor (IOL) for various reasons. Observational studies have shown that nulliparous women with an unfavorable cervix undergoing induction of labor have about a two-fold increased risk of cesarean delivery. Urgent cesarean section during labor has additional risks for maternal and/or fetal complications as compared with elective cesarean delivery. The risks of a cesarean delivery are not limited to the index pregnancy but also implicate future pregnancies. Thus, identification of women at high risk for cesarean delivery before the induction of labor process has a significant clinical value. The Bishop score remains the standard method for predicting the duration and safety of induced labor. However, this method of assessment is subjective and was shown to be a poor predictor for the outcome of labor in women scheduled for induction. Sonographic measurement of cervical length, before induction of labor was suggested as a predictor of a successful induction. Nevertheless, a recent meta-analysis has shown that cervical length has only moderate capacity in the prediction of induction outcome. Currently, there is no objective and reliable way to predict a successful induction of labor.