Progestational agents to prevent preterm birth: a meta-analysis of randomized controlled trials

Obstet Gynecol. 2005 Feb;105(2):273-9. doi: 10.1097/01.AOG.0000150559.59531.b2.


Objective: To perform an updated systematic review with meta-analysis to further elucidate the efficacy of progestational agents for the prevention of preterm births in patients at elevated risk.

Data sources: Computerized databases, references in published studies, and textbook chapters in all languages were used to identify randomized controlled trials (RCTs) evaluating the use of progestational agents for the prevention of preterm births in women at elevated risk.

Methods of study selection: We identified RCTs that compared progestational agents with placebo for patients at risk for preterm birth and evaluated at least one of the following: delivery before 37 weeks of gestation, birth weight less than 2,500 g, threatened preterm labor, respiratory distress syndrome, and perinatal mortality. The primary outcomes assessed were preterm delivery and perinatal mortality.

Tabulation, integration, and results: Ten studies met inclusion criteria for this review. For each study with binary outcomes, an odds ratio (OR) with 95% confidence intervals (CIs) was calculated for selected outcomes. Homogeneity was tested across the studies. Compared with women allocated to receive placebo, those who received progestational agents had lower rates of preterm delivery (26.2% versus 35.9%; OR 0.45, 95% CI 0.25-0.80). Similar results were noted when comparing patients who were specifically treated with 17alpha-hydroxyprogesterone caproate (29.3% versus 40.9%; OR 0.45, 95% CI 0.22-0.93). Additionally, subjects allocated to receive 17alpha-hydroxyprogesterone caproate had lower rates of birth weights less than 2,500 g (OR 0.50, 95% CI 0.36-0.71). No differences in rates of hospital admissions for threatened preterm labor or perinatal mortality were noted for subjects receiving progestational agents in general or for those receiving only 17alpha-hydroxyprogesterone caproate specifically.

Conclusion: The use of progestational agents and 17alpha-hydroxyprogesterone caproate reduced the incidence of preterm birth and low birth weight newborns.

Publication types

  • Comparative Study
  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • 17 alpha-Hydroxyprogesterone Caproate
  • Adolescent
  • Adult
  • Confidence Intervals
  • Female
  • Follow-Up Studies
  • Gestational Age
  • Humans
  • Hydroxyprogesterones / therapeutic use*
  • Incidence
  • Medroxyprogesterone Acetate / therapeutic use*
  • Odds Ratio
  • Pregnancy
  • Pregnancy Outcome*
  • Pregnancy, High-Risk*
  • Premature Birth / epidemiology
  • Premature Birth / prevention & control*
  • Prenatal Care / methods
  • Randomized Controlled Trials as Topic
  • Reference Values
  • Risk Assessment
  • Treatment Outcome


  • Hydroxyprogesterones
  • 17 alpha-Hydroxyprogesterone Caproate
  • Medroxyprogesterone Acetate