Prophylactic administration of progesterone by vaginal suppository to reduce the incidence of spontaneous preterm birth in women at increased risk: a randomized placebo-controlled double-blind study

Am J Obstet Gynecol. 2003 Feb;188(2):419-24. doi: 10.1067/mob.2003.41.


Objective: The purpose of this study was to evaluate the effect of prophylactic vaginal progesterone in decreasing preterm birth rate in a high-risk population.

Study design: A randomized, double-blind, placebo-controlled study included 142 high-risk singleton pregnancies. Progesterone (100 mg) or placebo was administered daily by vaginal suppository and all patients underwent uterine contraction monitoring with an external tocodynamometer once a week for 60 minutes, between 24 and 34 weeks of gestation. Progesterone (n = 72) and placebo (n = 70) groups were compared for epidemiologic characteristics, uterine contraction frequency, and incidence of preterm birth. Data were compared by chi(2) analysis and Fisher exact test.

Results: The preterm birth rate was 21.1% (30/142). Differences in uterine activity were found between the progesterone and placebo groups (23.6% vs 54.3%, respectively; P <.05) and in preterm birth between progesterone and placebo (13.8% vs 28.5%, respectively; P <.05). More women were delivered before 34 weeks in the placebo group (18.5%) than in the progesterone group (2.7%) (P <.05).

Conclusion: Prophylactic vaginal progesterone reduced the frequency of uterine contractions and the rate of preterm delivery in women at high risk for prematurity.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Birth Rate
  • Double-Blind Method
  • Female
  • Humans
  • Obstetric Labor, Premature / prevention & control*
  • Placebos / therapeutic use
  • Pregnancy
  • Progesterone / administration & dosage*
  • Risk Factors
  • Suppositories
  • Uterine Contraction / drug effects


  • Placebos
  • Suppositories
  • Progesterone