Physical Examination-Indicated Repeat Cerclage in Singleton Pregnancies: A Retrospective Cohort Study

Objective Cervical insufficiency is a significant cause of mid-trimester miscarriage and preterm birth, for which cervical cerclage is the standard treatment. However, some patients experience extreme preterm delivery even after undergoing a repeat cerclage following initial cerclage failure. This study aimed to investigate the optimal timing for repeat cerclage and to identify independent predictors of its failure. Methods The sociodemographic characteristics and clinical data of 47 singleton pregnancies who underwent a repeat cerclage at Fujian Maternity and Child Health Hospital from October 2018 to May 2025 were retrospectively analyzed. Participants were divided into a failure group and a success group. The failure group included 17 patients with delivery < 28 weeks, while the success group included 30 patients with delivery ≥ 28 weeks. Univariate and multivariate logistic regression analyses were used to identify independent risk factors. Receiver operating characteristic (ROC) curves were employed to determine optimal cut-off values for key continuous variables. Moreover, the BP neural network was used to perform a secondary validation of the independent risk factors. Results Multivariate analysis revealed that cervical dilation before repeat cerclage (OR = 5.864, 95%CI: 1.164–29.555), elevated neutrophil-to-lymphocyte ratio (NLR) (OR = 4.116, 95%CI: 1.17–14.484), and positive cervical culture (OR = 168.449, 95% CI: 3.588–7909.002) were independent risk factors for repeat cerclage failure. ROC curve analysis indicated that preoperative cervical dilation ≥ 1.75 cm (AUC = 0.76) and NLR ≥ 4.9 (AUC = 0.83) had good predictive efficacy for failure. The factor weights in the BP neural network further demonstrated that cervical dilation before repeat cerclage, elevated NLR, and positive cervical culture are the three most influential independent risk factors for repeat cerclage failure. Conclusion The degree of preoperative cervical dilation, systemic inflammation indicated by NLR, and local cervical infection are key predictors of repeat cerclage failure. The optimal timing for repeat cerclage is when cervical dilation is less than 2 cm and there is no inflammatory or infectious status.