Preterm birth (PTB) remains a leading cause of neonatal morbidity and mortality in the United States and worldwide. Efforts to predict and delay preterm birth have been largely unsuccessful thus far. This paper seeks to illuminate the history and relevant discoveries regarding the role of progesterone in the prevention of PTB, which includes maintaining quiescence of the myometrium and counteracting cervical ripening. We will review the outcomes and methodologies of recent clinical trials, which have led to debate over the efficacy of progesterone in delaying PTB among at-risk women. The aim of this paper is to explore the historical and scientific basis for progestin treatments in the prevention of PTB, briefly discuss the results of recent clinical trials, and suggest direction for future research.
Keywords: preterm birth, labor, progesterone, progestin, trimegestone, uterine myometrium, cervix