Prematurity is the leading cause of neonatal death and handicap. Although all births before 37 weeks of gestation are defined as preterm, most damage and death occurs in infants delivered before 34 weeks. Improvements in neonatal care have led to higher rates of survival among very premature infants, but a major effect on the associated mortality and morbidity will be achieved only by better identification of women at high risk for preterm delivery and by development of an effective intervention to prevent this complication. The prophylactic administration of progesterone beginning in mid-gestation to women who previously had a preterm birth has been shown to reduce the rate of recurrence. Also use of prophylactic cervical cerclage reduces preterm labour but the preference of which method remains an area of discussion.