Reproductive success is critical for survival of the species. The timely onset of labor and
delivery is an important determinant of perinatal outcome. Preterm birth (defined as delivery
before 37 weeks' gestation) and post-term pregnancy (defined as pregnancy continuing
beyond 42 weeks) are both associated with a significant increase in perinatal morbidity and
mortality. The factors responsible for the timing of labor in the human are complex and, as
yet, are not completely understood. This article reviews the current understanding of the�…