Prevention of preterm birth based on short cervix: progesterone.

Preterm delivery, which occurs in about 5%-13% of pregnancies in most countries, is the main cause of neonatal morbidity and mortality. Symptomatic treatment of pregnancies presenting in preterm labor with corticosteroids has improved perinatal outcome but has not reduced the incidence of preterm delivery. Recent evidence suggests that the rate of preterm delivery may be reduced by the prophylactic use of progesterone in women with a history of preterm delivery and in those with a short cervical length identified by routine transvaginal sonography. This review summarizes the evidence (level A evidence) of the effectiveness of progesterone on the rate of preterm birth.