Prevention of preterm delivery.

Preterm birth is defined as birth before the completion of 37 weeks of gestation. The frequency of preterm birth in the United States increased from 10.7% in 1992 to 12.3% in 2003. 1 Preterm births can be categorized as those undertaken because of a specific indication or as spontaneous preterm births. Indicated preterm births occur when a health care provider delivers a baby because of medical or obstetrical complications that jeopardize the health of the mother or the fetus. Spontaneous preterm births occur as a consequence of spontaneous preterm labor or preterm rupture of fetal membranes before the onset of labor. This review focuses on therapeutic strategies for the prevention and treatment of spontaneous preterm labor and delivery.