Effective Ways to Prevent Preterm Birth in High-Risk Women

Both vaginal progesterone and cervical cerclage can effectively prevent preterm birth in women at risk for spontaneous preterm birth, according to the results of an adjusted indirect meta-analysis of randomized controlled trials.¹
   
In the absence of any studies that have directly compared vaginal progesterone with cervical cerclage for preventing preterm birth, researchers indirectly compared these interventions to help physicians determine the optimal method of prolonging pregnancies and minimizing adverse outcomes related to preterm birth. Included in their systematic review and meta-analysis were 4 studies (n=158 patients) that evaluated vaginal progesterone versus placebo and 5 studies (n= 504 patients) that compared cerclage with no cerclage. All patients had a sonographically confirmed cervical length of less than 25 millimeters in the mid trimester, a singleton gestation, and a previous spontaneous preterm birth.
   
Both vaginal progesterone and cerclage, compared with placebo and no cerclage, were associated with significant reductions in both risk of preterm birth at less than 32 weeks’ gestation and risk of composite perinatal morbidity and mortality. Specifically, when vaginal progesterone was used, the risk of preterm birth was reduced by 53%, the risk of composite perinatal morbidity and mortality was reduced by 57%, and the rates of composite neonatal morbidity and admission to the neonatal intensive care unit were decreased significantly when compared with placebo. The use of cervical cerclage, when compared with no cerclage, was associated with a 34% reduction in the risk of preterm birth at less than 32 weeks’ gestation, a 36% decrease in the risk of composite perinatal morbidity and mortality, and significantly lower rates of preterm birth at less than 37, 35, and 28 weeks’ gestation and birthweight of less than 2500 grams.

The effectivess of vaginal progesterone and cervical cerclage in the prevention of preterm birth or adverse perinatal outcomes, however, were not significantly different. In light of these findings, the review authors recommend that treatment selection be determined after considering the adverse effects and cost-effectiveness of each intervention in addition to the patient’s and physician’s preference. The authors also recommend that if daily vaginal progesterone is the chosen intervention but 17 alpha-hydroxyprogesterone caproate (17P) had previously been prescribed because of a history of spontaneous preterm birth, the use of 17P should be discontinued. The study authors offer this recommendation because there is no evidence that 17P reduces the risk of preterm birth in women with a shortened cervix.²

Pertinent Points:
- Vaginal progesterone or cervical cerclage significantly reduces the risk of preterm birth in women with a singleton gestation who have a shortened cervix and who previously have had a preterm birth.
- The optimal treatment should be based on patient and physician preferences as well as considerations for the cost-effectiveness of and the adverse events associated with each intervention.
 

References:

1. Conde-Agudelo A, Romero R, Nicolaides K, et al. Vaginal progesterone vs cervical cerclage for the prevention of preterm birth in women with a sonographic short cervix, previous preterm birth, and singleton gestation: a systematic review and indirect comparison metaanalsysis. Am J Obstet Gynecol. 2013;208:42.e1-18.
2. Berghella V, Figueroa D, Szychowski JM, et al. 17 alpha-hydroxyprogesterone caproate for the prevention of preterm birth in women with prior preterm birth and a short cervical length. Am J Obstet Gynecol. 2010;202:351.e1-351.e6.