Abstract

ABSTRACT Background: Cervical length and Bishop Score are known to be good predictors of successful induction of labor, but little is known about the association between cervical funneling and labor induction. The study aims to determine the predictive value of cervical funneling in successful induction of labor and compare the strength of association between cervical length, Bishop score, cervical funneling in the successful prediction of labor. Material and Methods: This is a comparative prospective observational cohort study conducted for the duration of 7 months. A single observer assessed sonographic cervical length and funneling. After sonography, the Bishop score was determined by digital examination by another observer. All the study subjects underwent a similar labor induction protocol and the collected data was analyzed. Results: The mean Bishop score was 5.4+/-1.39 and the mean TVS cervical length was found to be 27.34 +/- 8.76 mm. For successful prediction of labor within 6 hours of induction initiation, Bishop score was found to be statistically highly significant with specificity of 85.71% and PPV of 92.9%. Whereas the sensitivity and NPV were comparable. The diagnostic accuracy was 67.06%. TVS cervical length also came out to be statistically highly significant with sensitivity 75%, specificity 80.95%, PPV 92.3%, NPV 51.5%. Diagnostic accuracy was 76.47%, i.e. more than Bishop score. Cervical funneling had sensitivity, specificity, PPV, NPV were 15.63%, 90.48%, 83.3%, 26% respectively at 95% CI and the diagnostic accuracy was 34.12%. This implies that in presence of funneling the likelihood of vaginal delivery increases significantly but its absence is not statistically significant in predicting labor induction outcome. Conclusion: This study demonstrates that Bishop score is a better predictor than TVS cervical length for successful induction of labor in term (>37 weeks) pregnancies. The probable reason could be that the Bishop score includes multiple factors like station of fetal head and other aspects of cervix like position, consistency, dilatation and effacement. Whereas, the presence of cervical funneling increases the likelihood of vaginal delivery in induced patients but its absence is of no significance in successful vaginal delivery.  Keywords: Cervical length, bishop score, cervical funneling, labor induction