The predictive role of uterine electromyography in delivery before 28 weeks of gestation after transvaginal cervical cerclage.

BACKGROUND

Delivery before 28 weeks of gestation is a major cause of perinatal morbidity and mortality. Cervical cerclage is widely used to prevent preterm birth (PTB), yet predicting outcomes after cerclage remains challenging. Uterine electromyography (uEMG), a noninvasive method that records myometrial electrical activity, offers objective and accurate assessment of uterine contractions. This study evaluated the predictive value of uEMG for delivery before 28 weeks of gestation in women with singleton pregnancies following transvaginal cervical cerclage.

METHODS

In this single-center retrospective study, 131 women with singleton pregnancies who underwent McDonald cervical cerclage and uEMG monitoring within 48 h postoperatively between January 2018 and February 2025 were included. Contraction-related indicators, including frequency, average peak intensity, and average duration, were analyzed. Multivariate logistic regression analysis was performed to identify independent predictors of delivery before 28 weeks, and a nomogram was developed. Model performance was assessed using receiver operating characteristic (ROC) curve, the area under the curve (AUC), calibration analysis, decision curve analysis (DCA), and a confusion matrix. Internal validity was evaluated through five-fold cross-validation.

RESULTS

Among 68 women without postoperative contractions, 3 (4.41%) delivered before 28 weeks, compared with 21 of 63 women with contractions (33.33%) (P < 0.001). The multivariate analysis identified an average peak intensity of ≥ 71.00 as an independent predictor of delivery before 28 weeks (P = 0.021). When combined with assisted reproductive technology (ART), cervical length, and previous late miscarriage, the average peak intensity yielded an AUC of 0.806. The model demonstrated high specificity (0.93) but modest sensitivity (0.52). Calibration analysis showed good concordance between predicted and observed outcomes, while DCA confirmed clinical utility within a risk threshold range of 0.38-0.82. Five-fold cross-validation further supported the model's robustness.

CONCLUSIONS

The average peak intensity of uterine contractions measured by uEMG is an independent predictor of delivery before 28 weeks in women undergoing cervical cerclage. The proposed nomogram provides a potentially practical tool for individualized risk stratification and management. Prospective multicenter studies with larger cohorts are warranted to validate the model and improve its predictive sensitivity.