Comparison of two emergency cervical cerclage techniques in twin pregnancies: A retrospective cohort study matched with cervical dilation

Objectives This retrospective cohort study aimed to assess the efficacy of emergency cervical cerclage (ECC) performed with the combined McDonald‐Shirodkar technique in twin pregnancies between 18 and 26 weeks of pregnancy with painless cervical dilation 1 to 6 cm. Methods A retrospective cohort study matched with the degree of cervical dilation was conducted. The study group (case group) included women with twin pregnancies undergoing combined McDonald‐Shirodkar approach with cervical dilation ≥1 cm between 18 to 26 weeks of gestation at four institutions, from December 2015 to December 2022. To minimize confounding factors, we elucidated the causality structure using a directed acyclic graph and performed 1:1 case–control matching. A control group underwent the McDonald approach. The primary outcome was gestational age (GA) at delivery. The secondary outcomes were pregnancy latency; the rates of spontaneous preterm birth at