Pregnancy outcomes of cerclage in twin gestations: a multicenter retrospective cohort study

Objectives: To determine the effects of cerclage on twin pregnancies. Methods: A multicenter, retrospective, cohort study was conducted at 10 tertiary centers using a web-based data collection platform. The study population included twin pregnancies delivered after 20 weeks of gestation. Patients with one or two fetal deaths before 20 weeks of gestation were excluded. Maternal characteristics, including prenatal cervical length (CL) and obstetric outcomes, were retrieved from the electronic medical records. Results: A total of 1,473 patients had available data regarding the CL measured before 24 weeks of gestation. Seven patients without CL data obtained prior to cerclage were excluded from the analysis. The study population was divided into two groups according to the CL measured during the mid-trimester: the CL ≤2.5 cm group (n = 127) and the CL >2.5 cm group (n = 1,339). A total of 127 patients (8.7%) were included in the CL ≤2.5 cm group, including 41.7% (53/127) who received cerclage. Patients in the CL >2.5 cm group who received cerclage had significantly lower gestational age at delivery than the control group (hazard ratio (HR): 1.8; 95% confidence interval (CI): 1.11–2.87; p = .016). Patients in the CL ≤2.5 cm group who received cerclage had a significantly higher gestational age at delivery than the control group (HR: 0.5; 95% CI: 0.30–0.82; p value = .006). Conclusions: In twin pregnancies with a CL ≤2.5 cm, cerclage significantly prolongs gestation. However, unnecessary cerclage in women with a CL >2.5 cm may result in a higher risk of preterm labor and histologic chorioamnionitis although this study has a limitation originated from retrospective design.