What question did this study set out to answer?

The study aims to assess the predictive accuracy of an ultrasound-based system compared to the Bishop score for successful labor induction.

February 28, 2026Open Access

Comparison of an Ultrasound-Based System and the Bishop Score for Predicting Labor Induction Timing in Singleton Pregnancies at Term: A Prospective Cohort Study

Key Points

The study aims to assess the predictive accuracy of an ultrasound-based system compared to the Bishop score for successful labor induction.
Conducted a prospective observational cohort study at a tertiary center in China.
Included women with term singleton pregnancies scheduled for induction of labor.
Used the LaborPro system to measure cervical length and fetal station.
Applied univariate and multivariate logistic regression analyses.
Calculated the area under the receiver operating characteristic curve for comparison.
43.8% of women (84 out of 192) achieved vaginal delivery within 24 hours of induction (VD24).
Cervical length and fetal station were identified as significant predictors of successful VD24.
A 1-cm increase in cervical length reduced odds of VD24 by 58% (OR 0.42).
A 1-cm descent in fetal station increased odds of VD24 by nearly fivefold (OR 4.84).
The integrated predictive model had higher accuracy (AUC = 0.856) than the Bishop score (AUC = 0.600).

Abstract

Purpose: This study aimed to evaluate the predictive accuracy of a modified cervical assessment model incorporating objective measurements from the LaborPro system for successful induction of labor (IOL) in term singleton pregnancies. Patients and Methods: This prospective observational cohort study was conducted at a tertiary center in China between August 2023 and November 2025. The study included women with term singleton pregnancies scheduled for IOL. Objective measurements of cervical length and fetal station were obtained using the LaborPro system, an ultrasound-guided magnetic tracking device. The primary outcome was successful IOL, defined as vaginal delivery within 24 hours of induction onset (VD24). Univariate and multivariate logistic regression analyses were employed to identify independent predictors, and the area under the receiver operating characteristic curve (AUC) was used to compare predictive performance. Results: Of the 192 eligible women undergoing IOL, 84 (43.8%) achieved VD24. Multivariate analysis identified cervical length and fetal station as significant independent predictors of VD24. Each 1-cm increase in cervical length was associated with a 58% reduction in the odds of VD24 Odds ratio (OR) 0.42, 95% confidence interval (CI) 0.19– 0.91, whereas each 1-cm descent in fetal station was associated with a nearly fivefold increase in the odds of VD24 (OR 4.84, 95% CI 2.05– 11.46). A combined model integrating objective assessments of cervical length and fetal station with clinical evaluations of cervical position and consistency demonstrated higher predictive accuracy (AUC = 0.856) compared to the traditional Bishop score (AUC = 0.600). Conclusion: Objective assessment of cervical length and fetal station using the ultrasound-based LaborPro system provides reliable, independent prediction of IOL success. The integrated predictive model significantly outperforms the Bishop score alone. These findings support the clinical utility of objective ultrasound-based evaluations, particularly for optimizing IOL management in nulliparous women. Keywords: ultrasound-based laborpro system, cervical ripening, induction of labor, prediction model, term pregnancy

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