Prevention of Preterm Birth With a Pessary in Singleton Gestations

Prevention of Preterm Birth With a Pessary in Singleton Gestations

Preterm birth (PTB) is associated with over one million infant deaths annually worldwide. The incidence of PTB in the United States is 11.5% with more than 500,000 deliveries occurring at less than 37 weeks gestation annually. The rate of PTB in the United States increased to 12.8% in 2006, and remains high compared to almost all other developed countries, despite the introduction of many public health and medical interventions designed to delay PTB. Weekly treatment with 17-alpha hydroxyprogesterone caproate beginning at 16-20 weeks gestation has been shown to significantly reduce the risk of PTB and is currently recommended for women who experienced spontaneous PTB in a prior pregnancy. However, a strategy for the prevention of spontaneous PTBs in which therapeutic intervention is restricted to women with a previous PTB is likely to have a small effect on the overall rate of prematurity since only about 10% of spontaneous PTBs arise in women with such a history. A major reduction in rates of mortality and morbidity in premature babies will only be achieved with increased precision in the identification of women at risk of spontaneous PTB and through the development of an effective prevention for this complication. Transvaginal ultrasound measurement of cervical length is a reliable screening test for prediction of PTB. Although treatment with vaginal progesterone is effective in decreasing PTB in women with a short cervix, over 30% of women still experience premature delivery and many women find daily administration of progesterone to be challenging. Preliminary studies have suggested that use of an intravaginal pessary may be effective in preventing PTB. If effective this approach would be particularly appealing because of the wide availability of pessaries, ease of use, and low cost. Unfortunately, existing studies are inadequate to confirm effectiveness; a well designed, properly powered, prospective randomized trial is warranted prior to widespread implementation in clinical practice. We propose such a trial to study the effectiveness of the pessary in decreasing the incidence of PTB in an inner city Philadelphia population.

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 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