Physical Exam Indicated Cerclage in Twin Gestations

Twin pregnancies have 50% 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. When cervical dilation is identified before 24 weeks in
singleton pregnancies, the risk of preterm birth is 90%-100%; based on a small series of
cases, approximately 50% of twin gestations with cervical dilation will be delivered prior to
viability (24 weeks) and the risk of preterm birth prior to 34 and 37 weeks was 85% and 100%.
Cervical dilation is the worst prognostic factor for preterm birth. There are a small number
of case reports of cervical cerclage in twin pregnancies with dilated cervix that suggest
similar outcomes to those in singleton pregnancies. The investigators' objective is to
determine if physical exam indicated cerclage reduces the incidence of spontaneous preterm
birth <34 weeks and improve perinatal outcome in asymptomatic women with twin gestations and
dilated cervix (1 to 5 cm) between 16 to 23 6/7 weeks of gestation.

Inclusion Criteria:

1. Pregnant women older than 18 years of age

2. Diamniotic twin pregnancy

3. Cervical dilation between 1 to 5 cm and/or visible membranes by pelvic exam or
speculum exam between at 16-23 6/7 weeks gestation

Exclusion Criteria:

1. Singleton pregnancy or higher order than twins multiple gestation

2. Cervical dilation more than 5 cm

3. Amniotic membranes prolapsed beyond external os into the vagina, unable to visualize
cervical tissue

4. More than 24 weeks of gestation

5. Multifetal reduction after 14 weeks

6. Monoamniotic twins

7. Twin-twin transfusion syndrome

8. Ruptured amniotic membranes at the time of diagnosis of dilated cervix

9. Major fetal structural anomaly

10. Fetal chromosomal abnormality

11. Cerclage already in place for other indications

12. Active vaginal bleeding

13. Suspicion of clinical or biochemical chorioamnionitis

14. Painful regular uterine contractions

15. Labor (progressing cervical dilation)

16. Placenta previa