Spontaneous preterm birth (SPTB) remains the number one cause of perinatal mortality in many countries, including the United States. Multiple gestations are at increased risk of SPTB. A short cervical length (CL) on transvaginal ultrasound (TVU) has been shown to be a good predictor of SPTB, in both singletons and twins.

The cervical pessary is a silicone device that has been used to prevent SPTB. The efficacy of the cervical pessary has been assessed in several populations including singletons with short CL, unselected twins, twins with short CL, and triplet pregnancies. Several randomized clinical trials (RCTs) have been published, and several are ongoing. However, no consensus on use of the cervical pessary in pregnancy or guidelines for management have been assessed.

Inclusion Criteria:

• 18-50 years of age
• Twin pregnancy (limits the participants to female gender)
• Short cervical length (less than or equal to 30 mm) on second trimester ultrasound at 18-23 6/7 weeks gestation

Exclusion Criteria:

• Singleton or higher order than twins multiple gestation
• Monoamniotic twins
• Twin twin transfusion syndrome
• Ruptured membranes
• Lethal fetal structural anomaly
• Fetal chromosomal abnormality
• Cerclage in place (or planned placement)
• Vaginal bleeding
• Suspicion of chorioamnionitis
• Ballooning of membranes outside the cervix into the vagina
• Painful regular uterine contractions
• Labor
• Placenta previa

outcomes assessor and data analyst