Evaluation of length, volume and gray-scale histogram of the cervix as predictors of successful induction

Abstract

Objective: The aim of this study was to evaluate whether the Bishop score, length, volume and gray-scale histogram of the cervix has a predictive value of assessing the rate of success in trial of induction. Methods: Forty-one nulliparous patients with its Bishop score six or less were enrolled for this prospective study. All were on prostaglandin (, Propess ; Controlled Therapeutics Ltd) pessary. Three-dimensional transvaginal ultrasound scans of the cervix were performed on the ACCUVIX XQ (Medison) to measure length, volume, and gray-scale histogram. Bishop score was determined by digital examination. The successful induction was defined as the ability to achieve the active phase of labor corresponding to a cervical dilatation of 4 cm within 12 hours of removing the pessary. The receiver operating characteristics (ROC) curves were also used to estimate an optimal cutoff point for the Bishop score, length, volume, and gray-scale histogram of the cervix. Logistic regression analysis was used for statistical analyses. Results: The overall successful rate of labor induction was 73.2% (30/41). Multiple logistic regression analyses demonstrated that the value of anterior lip histogram was significantly associated with the successful labor induction. ROC curve for anterior lip histogram value in predicting success of induction indicated a significant relationship with successful induction. The best cutoff value was 69.4. Conclusion: The value of anterior lip histogram associates significantly with the prediction of successful induction in nulliparous women. But, Bishop score and other sonographic measurement of cervical length, volume, and posterior lip histogram have no predictive values for successful induction.