OP22.03: Prediction of failed labor induction in multiparous women at term: role of previous obstetric history, digital examination, and sonographic measurement of cervical length

Abstract

The purpose of this study was to examine the predictive value of previous obstetric history, Bishop score, and sonographic measurement of cervical length for predicting failed labor induction in multiparous women at term. This prospective observational study enrolled 110 consecutive multiparous women with singleton gestations scheduled for labor induction at term. Transvaginal ultrasound for measurement of cervical length was performed and the Bishop score was assessed by digital examination. Receiver operating characteristic (ROC) curves and logistic regression were used for statistical analysis. Labor induction failed in 15 women (14%). In terms of previous obstetric history, women with only previous mid-trimester loss or preterm delivery had a significantly higher risk of failed labor induction than those with at least one previous term delivery. Logistic regression demonstrated that both previous obstetric history and the Bishop score were found to be significant and independent contributing factors for failed labor induction. Further examination of the different components of the Bishop score showed that only previous obstetric history provided a significant contribution to the prediction of failed labor induction. To predict the failure of labor induction, the best cut-off value of Bishop score was 3, with a sensitivity of 73% and a specificity of 44%. The previous obstetric history and the Bishop score independently predicted the failure of labor induction in multiparous women. However, sonographic measurement of cervical length appeared to have poor predictive value for the risk of failed induction.