Long-term outcomes of moderately preterm, late preterm, and early term infants.

At present, moderate preterm (MPT) infants born at 32 to 33 weeks' gestation and late preterm (LPT) infants born at 34 to 36 weeks' gestation make up the largest subgroup of preterm infants and contribute to more than 80% of premature births in the United States. There is increasing evidence that both MPT and LPT infants are at increased risk of neurologic impairments, developmental disabilities, school failure, and behavior and psychiatric problems. Population studies suggest that for each 1 week decrease in gestational age below 39 weeks, there are stepwise increases in adverse outcomes after adjusting for confounders.