Prediction of successful induction of labour with dinoprostone in a homogeneous group of patients

Abstract

Objectives. The aim of the present study was to compare the efficiency of transvaginal ultrasonography and the Bishop’s scoring system in predicting the success of labour induction.
Methods. Transvaginal ultrasonography for cervical evaluation and cervical palpation for Bishop scoring were performed in all patients by the same obstetrician. This prospective study was conducted in the Perinatology and Maternity Care Unit of Etlik Zübeyde Hanim Maternity and Women’s Health Teaching and Research Hospital between September 2007 and February 2008. Eighty-four patients induced with prostaglandin E2 (dinoprostone) for medical indications were included in the study.
Results. No significant association was found between transvaginal measurement of cervical length and the success of labour induction (p=0.201). We found no statistically significant difference between failure of labour induction and successful labour induction in terms of transvaginal measurement of cervical length (area under the curve (AUC) 0.583; 95% confidence interval (CI) 0.452 - 0.714). A significant association between the Bishop’s score and failure of labour induction (p=0.029) was found. A statistically significant relationship was found between failure of labour induction and successful labour induction in terms of the Bishop’s score (AUC 0.632; 95% CI 0.513 - 0.751). The best cut-off point for predicting successful labour induction was a Bishop’s score of 2 or more. The sensitivity and specificity levels associated with this point were 82.4% and 44.9%, respectively (positive predictive value 50.9% and negative predictive value 78.6%).
Conclusions. Bishop’s scoring system was more successful than assessment of cervical length by ultrasound in predicting failed induction in a homogeneous group of patients in whom labour was induced with prostaglandin E2.