Spontaneous preterm birth (SPTB) remains the number one cause of perinatal mortality in many countries, including the United States. In singleton gestations a short cervical length (CL) on transvaginal ultrasound (TVU) has been shown to be a good predictor of SPTB.

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

Inclusion Criteria:

• 18-50 years of age
• Singleton pregnancy (limits the participants to female gender)
• Short cervical length (less than or equal to 25 mm) on second trimester transvaginal ultrasound at 18-23 6/7 weeks gestation

Exclusion Criteria:

• Multiple gestation
• Prior spontaneous preterm birth 16-36 6/7 weeks
• 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 or CL = 0 mm on transvaginal ultrasound
• Painful regular uterine contractions
• Placenta previa