OP22.04: Prediction of successful labor induction in twin gestation: body mass index, digital examination, and sonographic measurement of cervical length

Abstract

The purpose of this study was to evaluate the predictive value of body mass index (BMI), Bishop score, and the sonographic measurement of cervical length for predicting successful labor induction (defined as an ability to achieve the active phase of labor within 1 day after induction) in twin gestations. This prospective observational study enrolled 50 consecutive women with twin pregnancy at more than 34.0 weeks of gestation scheduled for induction of labor. Transvaginal ultrasound for measurement of cervical length was performed and the Bishop score was assessed by digital examination. Univariate and multivariate analyses were used for statistical analysis. Labor induction was successful in 52% (26/50). Women who had successfully induced labor revealed significantly lower BMI and a lower rate of Cesarean delivery than those who failed to induce labor. However, no significant differences were found regarding median gestational age at the time of labor induction, median cervical length, median Bishop score, distribution of parous and nonparous women, the prevalence of prostaglandin use, and the median birth weight between these two patient groups. To predict the success of labor induction, the best cut-off value of BMI was 29, with a sensitivity of 77% and a specificity of 62%, respectively. Multiple logistic regression demonstrated that only BMI provided a significant contribution to predicting successful labor induction. The BMI independently predicted the success of labor induction in twin gestation. However, sonographic measurement of cervical length and Bishop score appeared to have poor predictive value for the likelihood of successful induction.