The Myometrium and Uterine Cervix in Normal and Preterm Labor

PRETERM labor remains the most important cause of perinatal morbidity and mortality. In this article we review our present understanding of the biochemistry and physiology of the myometrium and uterine cervix, particularly as they relate to the pathogenesis and therapy of preterm labor.During pregnancy, the myometrium relaxes to accommodate the developing infant and products of conception, and at the end of pregnancy, it provides the rhythmic tonic contractions of labor that facilitate expulsion of the uterine contents. As in all muscle tissue, myometrial contractility is based on the interaction of the contractile proteins actin and myosin. Many, if not . . .