Predictive Value of Transvaginal Ultrasonographic Cervical Assessment versus Bishop Score in Induction of Labour: A Comparative Cross-sectional Study
DOI:
https://doi.org/10.64252/2zdt5c85Keywords:
Transvaginal Ultrasonography, Cervical Length, Bishop Score, Labour Induction, Funnel Length, Cervical Assessment, Ultrasound Scoring, Parity, Obstetric UltrasoundAbstract
Background: Induction of labour (IOL) is one of the most frequently performed obstetric interventions. Accurate prediction of induction success is crucial to minimize failed inductions and unnecessary caesarean sections. The Bishop score, though widely used, is subjective and has limited reproducibility. Transvaginal ultrasonography (TVS) offers an objective method for assessing cervical readiness.
Objective: To compare the predictive accuracy of transvaginal ultrasonographic cervical assessment using the Manipal Cervical Scoring System with the Modified Bishop Score in determining the success of induction of labour, and to analyse the influence of parity on induction outcomes.
Methods: This cross-sectional observational study included 89 term pregnant women (37–42 weeks) undergoing labour induction at a tertiary hospital. Pre-induction cervical assessment was performed by both TVS and digital examination by independent, blinded observers. Induction was carried out using intracervical prostaglandin E₂ with oxytocin augmentation as needed. The predictive value of each scoring system was evaluated by receiver operating characteristic (ROC) analysis, and independent predictors of successful induction were identified using binary logistic regression.
Results: Of the participants, 67.4 % entered active labour within 24 hours, and 56.2 % delivered vaginally. TVS score demonstrated superior predictive accuracy (AUC = 0.983, specificity = 100 %) compared with the Bishop score (AUC = 0.896, specificity = 89.7 %). Among TVS parameters, funnel length (OR = 16.98, p = 0.01) and cervical length (OR = 4.33, p = 0.01) were the most significant predictors, while cervical position was the only Bishop component significantly associated with active labour (p = 0.009). Multiparous women had shorter induction-to-delivery intervals (p = 0.007*) and higher vaginal delivery rates.
Conclusion: The Manipal TVS cervical score provides a superior, objective, and reproducible tool for predicting the outcome of labour induction compared with the Bishop score. Integration of TVS cervical assessment into pre-induction protocols can improve patient selection and reduce unnecessary caesarean deliveries.
