Late Preterm Infants, Early Term Infants, and Timing of Elective Deliveries

Delivery of infants who are physiologically mature and capable of suc-cessful transition to the extrauterine environment is an important priority for obstetric practitioners [1]. A corollary of this goal is to avoid iatrogenic complications of prematurity and maternal complications from delivery. It is generally accepted that births should occur at a minimum of 39 weeks’ gestation unless earlier delivery occurs spontaneously or because of mater-nal or fetal medical indications. During the past 15 years in the United States, however, the percentage of infants born before 40 weeks ’ gestation has dramatically increased and the percentage of infants born after 40 weeks’ gestation has decreased [2,3]. The shift in gestational age at birth raises the risk for the birth of physiologically immature infants and associated compli-cations. The purpose of this review is to describe the consequences of birth before physiologic maturity in late preterm and term infants, to identify fac-tors contributing to the decline in gestational age of deliveries in the United States, and to describe strategies to reduce premature delivery of late preterm (34 0/7–36 6/7 weeks ’ gestation) and early term infants (37 0/7–38 6/7 weeks ’ gestation) (Fig. 1). Consequences after birth for late preterm infants and early term infants During the past decade in the United States, delivery of late preterm in-fants and infants aged 37 0/7 to 39 6/7 weeks ’ gestation has increased byClin Perinatol 35 (2008) 325–34114 % and 21%, respectively, whereas births of infants after 40 weeks’ * Corresponding author