Ultrasound-Indicated Cerclage in Twin Pregnancies: A Cohort Study

Background. To report the pregnancy and neonatal outcomes in patients with twin pregnancies who underwent ultrasound-indicated cerclage (UIC) and to compare them to patients with singleton pregnancies undergoing the same procedures. Methods. Patients who underwent UIC between January 2010 and December 2020 at Kangnam Sacred Heart Hospital were reviewed. We compared characteristics, pregnancy, and neonatal outcomes between patients with singleton and twin pregnancies. Results. A total of 94 women (56 singleton and 38 twin pregnancies) underwent UIC were included. The mean gestational age (GA) at cerclage and preoperative cervical length (CL) were not significantly different. Twin pregnancies were more likely to deliver at earlier median gestations than singletons (singleton, 36+1 weeks vs twin, 32+6 weeks, and p=0.004). The frequency of preterm delivery <34 weeks in twin group was higher than in singleton group (15 (26.8%) vs 20 (52.6%) and p =0.016). However, the frequency of preterm delivery <32, <28, and <24 weeks was not significantly different between two groups. Although neonatal weights in singleton pregnancies were heavier than twin pregnancies, neonatal mortality and morbidities were not significantly different between two groups. Among various factors contributing to preterm birth, preoperative CL <= 15 mm was independently associated with a higher risk of preterm delivery before 34 weeks. Furthermore, pregnancy and neonatal outcomes of twin pregnancies with cervical length <= 15 mm are comparable with those of singleton pregnancies (GA at delivery, singleton, 35+1 weeks vs twin, 32+5 weeks, and p=0.24; neonatal mortality, singleton, 3.4% vs twin, 4.8%, and p=0.64). Conclusion. The pregnancy and neonatal outcomes of UIC in twin pregnancies were comparable to those in singleton pregnancies, especially when CL is <= 15 mm. UIC might be considered a safe procedure for twin pregnancies.