Validity of Clinical and Ultrasound Variables to Predict the Risk of Cesarean Delivery After Induction of Labor

OBJECTIVE: To evaluate a previously described score to predict the risk of cesarean delivery after induction of labor. METHODS: We conducted a multicenter prospective study among women at 36 weeks of gestation or more undergoing induction of labor in the maternity units of Geneva, Switzerland, and Novi Sad, Serbia. Before induction, we calculated the risk score for cesarean delivery including data on maternal height, body mass index, parity, and transvaginal ultrasonographic cervical length. We calculated the sensitivity and specificity of the score using different cutoffs of calculated risk. RESULTS: Of the 537 women included in the analysis, 92 (17%) had a cesarean delivery. Among the variables tested, only the transvaginal ultrasonographic cervical length was associated with the risk of cesarean delivery (P<.001). Using the different cutoffs of calculated risk of cesarean delivery (20%, 30%, and 40%), we calculated the sensitivity (69.6%, 54.3%, and 45.7%, respectively), specificity (42.0%, 58.2%, and 69.2%, respectively), and positive predictive value (19.9%, 21.0%, and 23.5%, respectively) of the risk score. The area under the receiver operating characteristic curve was 0.59. There was a poor association between the outcome of labor induction (vaginal delivery or cesarean delivery) and the predicted risk. CONCLUSION: The evaluated score was not useful to predict the outcome of women undergoing labor induction. Our results show the necessity of validating existing scores in different settings and patient populations before widespread implementation in clinical care. (Obstet Gynecol 2012; 120: 53-9) DOI: 10.1097/AOG.0b013e31825b9adb LEVEL OF EVIDENCE: II