Cerclage for Twins With Short Cervical Length ≤ 15mm

Twin pregnancies have 59% incidence of preterm delivery (before 37 weeks of gestation), with increased perinatal mortality and neonatal morbidity. No therapy has proven effective in preventing preterm birth in twins. The transvaginal cervical length (TVCL) performed before 24 weeks have been determined to be the best tool to identified women with twin pregnancy at risk of preterm birth (PTB). When short TVCL is identified before 24 weeks, the risk of preterm birth is 60%-70% for TVCL ≤25mm and 80%-90% for TVCL ≤15mm. There are a small number of case reports of cervical cerclage in twin pregnancies with cervical length ≤15mm that suggest decreased preterm birth by 80%. The investigators' objective is to determine if ultrasound indicated cerclage in reduces the incidence of spontaneous preterm birth \<34 weeks and improve perinatal outcome in asymptomatic women with twin gestations and cervical length ≤15mm between 16 to 23 6/7 weeks of gestation.