Delivery of infants who are physiologically mature and capable of successful transition to the extrauterine environment is an important priority for obstetric practitioner. A corollary of this goal is to avoid iatrogenic complications of prematurity and maternal complications from delivery. The purpose of this review is to describe the consequences of birth before physiologic maturity in late preterm and term infants, to identify factors contributing to the decline in gestational age of deliveries in the United States, and to describe strategies to reduce premature delivery of late preterm and early term infants.