Does increasing body mass index affect cerclage efficacy?

ABSTRACT

OBJECTIVE: To study the relationship between body mass index (BMI) and gestational age (GA) at delivery in patients with cervical insufficiency (CI) undergoing cerclage. STUDY DESIGN: We accessed a database of patients with singleton gestations undergoing cerclage (N=168) for a well-characterized history of CI, shortened cervix <2.5 cm with a history of prior preterm delivery or prolapse of membranes through the external os. Univariate and multivariate logistic regression analysis were performed to compare obstetrical outcomes between obese and normal-weight patients. RESULT: Prior preterm delivery <35 weeks in obese vs normal-weight patients was significantly higher (44% vs 9%), odds ratio=6.9 (95% CI 2.5, 18.5), with lower mean GA at delivery (32.6±7.0 vs 37.2±3.4 weeks, P<0.001). After controlling for confounders, BMI remained significantly predictive of prematurity (coefficient -0.12, adjusted R (2)=0.24), such that every additional 1 unit of BMI was associated with a 1-day reduction in GA at delivery (P=0.03). CONCLUSION: An inverse correlation exists between BMI and GA at delivery in patients with CI receiving cerclage. The findings are unexpected given the protective effect of obesity on spontaneous preterm delivery.