A nomogram for predicting prognosis of patients with cervical cerclage

Cervical insufficiency is an increased risk of midterm miscarriage and early preterm birth which increase the risk of fetal loss. This study aimed to construct a nomogram for patients with cervical insufficiency after cervical cerclage, which may assist clinicians to have individualized treatment for patients with cervical insufficiency.

A study was done retrospectively from January 2013 through July 2022 in our hospital. The primary outcomes were delivered at more than 28, 30, 32, or 34 gestational weeks. Kaplan-Meier curves were applied to analyze 17 variables. All patients were randomly split (147:64) into development and validation cohorts. Based on the multivariate Cox regression analysis, a nomogram was constructed through the 'rms' package in R.

A total of 211 patients with cervical insufficiency were enrolled: 121 had history-indicated cerclage; 58 had ultrasound-indicated cerclage and 32 had emergency cerclage. Times of gestations, times of miscarriages, IVF, abdominal pain, diagnostic classification, preoperative and postoperative management were demonstrated to impact overall extended days when delivering at more than 28 gestational weeks was set as the primary outcome. Except for preoperative and postoperative management, the above other five variables impacted the primary outcomes of delivering at more than 30, 32, or 34 gestational weeks. Postoperative tocolytics had an impact on the prognosis of patients who delivered at more than 30 gestational weeks. In development cohort data, a nomogram was established to predict overall extended days of patients with cervical cerclage. In present study, C-index was 0.662 in the development cohort and 0.687 in the validation cohort respectively, suggesting that the model presented some satisfied prediction. Moreover, the clinical decision curves for patients with delivering at more than 28, 30, 32 or 34 weeks set as primary outcomes also displayed that this nomogram demonstrated good clinical predictive usefulness.

The nomogram developed in this study may be a valuable tool assisting clinicians to evaluate outcomes of patients with cervical insufficiency after cervical cerclage, which helps them develop individualized management for the patients.