Does suture number matter in transvaginal cervical cerclage? A propensity score-weighted cohort study

Abstract Purpose To evaluate whether the number of sutures used during transvaginal cervical cerclage influences obstetric and neonatal outcomes when surgical technique, suture material, and perioperative management are standardized. Methods This retrospective cohort study included 125 women who underwent transvaginal cervical cerclage using identical monofilament suture material. Cerclage was performed with either a single suture (n = 23) or a double suture (n = 102) in this non-randomized observational cohort. The primary outcome was term delivery (≥ 37 weeks’ gestation). Secondary outcomes included gestational age at delivery and selected neonatal outcomes. To address non-random allocation and baseline group imbalance, propensity scores were estimated using pre-treatment maternal, obstetric, and clinical severity variables. Stabilized inverse probability of treatment weighting (IPTW) with truncation was applied, and doubly robust outcome models were used to estimate adjusted associations. Neonatal outcomes were analyzed at the pregnancy level to account for clustering in twin gestations. Results Women receiving double-suture cerclage presented at earlier gestational ages and with greater markers of cervical severity at baseline; however, after IPTW and doubly robust adjustment accounting for these baseline differences, no statistically significant difference in term delivery was observed. Secondary obstetric outcomes, including gestational age at delivery, were also comparable between groups after adjustment. Pregnancy-level neonatal outcomes, including NICU admission and neonatal mortality, did not differ meaningfully by suture number. Sensitivity analysis restricted to singleton pregnancies and stratified by cerclage indication yielded consistent results. Conclusion After accounting for baseline cervical severity and clinical indication, single- and double-suture transvaginal cerclage was associated with comparable obstetric and neonatal outcomes under standardized surgical conditions. These findings suggest that cervical status at the time of cerclage placement, rather than the number of sutures applied, is the primary determinant of outcome.