Vaginal Progesterone, Cerclage or Cervical Pessary for Preventing Preterm Birth in Asymptomatic Singleton Pregnant Women With a History of Preterm Birth and a Sonographic Short Cervix

Abstract

A major effort to decrease preterm birth rates is directed at preventing recurrent spontaneous preterm birth in singleton pregnancies. Shortened cervical length is one predictor of spontaneous preterm birth, and cervical pessary and cerclage are often used. This study was undertaken to compare the outcomes in women with a singleton pregnancy and history of preterm birth and sonographic short cervix, managed with cerclage, vaginal progesterone, or cervical pessary. The 3 cohorts of asymptomatic women had a singleton pregnancy, a history of at least 1 spontaneous preterm birth at less than 34 weeks, and a short cervix on ultrasonography. Cohort A included 142 women (United States) initially treated with cerclage (with or without 17α-hydroxyprogesterone caproate); cohort B comprised 59 women (United Kingdom) treated with vaginal progesterone followed by cerclage in cases of progressive cervical shortening, and cohort C had 42 women from Spain treated with cervical pessary. Women in cohort A had 1 prior spontaneous preterm birth and received cerclage when the cervical length was less than 25 mm. Management after cerclage followed standard protocols, and the cerclage suture was removed at 37 weeks’ gestation. For cohort B, short cervix was defined as 30.5 mm at 16 weeks’ gestation and 24.5 mm at 23 weeks’ gestation. Women were prescribed 200 mg vaginal progesterone. If additional significant cervical shortening was noted after treatment began, ultrasound-indicated cerclage was performed. In cohort C, serial transvaginal scans of the cervix started at 16 weeks’ gestation and continued at 1- to 4-weekly intervals. The pessary was removed at 37 weeks. Outcomes assessed included preterm births before 37, 34, and 28 weeks’ gestation; cesarean delivery; perinatal losses; and serious neonatal morbidity. The demographic characteristics of the 3 cohorts were similar but with slight differences in ethnicity/race among the groups. In cohort A, 38% of women also indicated an intent to receive weekly injections of 17α-hydroxyprogesterone caproate. Seven women (12%) in cohort B had rescue treatment because of progressive cervical shortening; 6 had cerclage, and 1 had a cervical pessary. The 3 groups did not differ significantly in the number of preterm births at less than 37 weeks (44%, 46%, and 45% for cohorts A, B, and C, respectively) or in rates of cesarean delivery (30%, 20%, and 24%, respectively). Fewer preterm births before 34 and 28 weeks’ gestation occurred in group C, but differences were not statistically significant except for births at less than 34 weeks in cohort B compared with cohort C (32% vs 12%; relative risk [RR], 2.70; 95% CI, 1.10–6.67). In comparing only the women with cervical length of less than 25 mm, regardless of gestational age, the difference between cohorts B and C was not statistically significant (RR, 2.21; 95% CI, 0.83–5.89). Neonatal deaths and serious neonatal morbidity were rare, and the 3 groups did not differ significantly. The available treatments for women with short cervix carry similar rates of effectiveness. Other than the higher incidence of preterm birth at less than 34 weeks’ gestation in cohort B compared with cohort C, no other comparisons were statistically significant. Without randomized cohorts and long-term safety data, the decision regarding which treatment options to choose should consider the preferences of the patient and clinician. International collaborations should be undertaken to investigate these treatments in adequately powered randomized trials that include low- and high-risk women.