Factors predictive of preterm birth following history-indicated vaginal cerclage

Abstract

To determine the predictive value of maternal, antepartum, and operative characteristics for preterm birth (PTB) following history (Hx)-indicated vaginal cerclage. Case-control study of patients undergoing Hx-indicated vaginal cerclage placement at a tertiary center 1/2013-4/2021. Multiple gestations and major fetal anomalies were excluded. Patients were categorized as having term birth or PTB (< 37 wks). Predictive variables (maternal demographics, antepartum characteristics, and operative features) were compared between groups. Bivariate logistic models were used to find potential exposures, which were included for a multivariate logistic model. Receiver operating characteristic (ROC) curve and area under the curve (AUC) were used for assessing model performance. Statistical significance was assessed at a 0.05 level. Of 175 cases analyzed, 89 (51%) had term birth and 86 (49%) a PTB. Patients with higher BMI at cerclage placement (OR 1.07 [95% CI 1.02-1.11]), fewer prior term births (OR 0.60 [CI 0.38-0.93]), and more prior midtrimester losses (OR 2.42 [1.56-3.75]) were more likely to have PTB. In our adjusted multivariable model, BMI at cerclage placement (aOR 1.05 [1.01-1.10]) and number of prior midtrimester losses (aOR 2.23 [1.42-3.48]) remained associated with PTB, but number of prior term births did not (aOR 0.62 [0.39-1.00]). The model including BMI (aOR 1.06 [1.01-1.10]) and prior midtrimester loss (aOR 2.25 [1.44-3.52]) was moderately predictive of PTB (AUC=0.73 [0.65-0.80]). Patients undergoing Hx-indicated cerclage with higher BMI at cerclage placement, fewer prior term births, and greater prior midtrimester losses have an increased risk of PTB. A two factor model was moderately predictive of PTB, which could prove helpful in counseling of future patients eligible for Hx-indicated cerclage.View Large Image Figure ViewerDownload Hi-res image Download (PPT)