Developmental Outcomes of Late-Preterm Infants at 2 and 4 Years Lenna Nepomnyaschy • Thomas Hegyi • Barbara M. Ostfeld • Nancy E. Reichman Published online: 17 July 2011 Ó Springer Science+Business Media, LLC 2011 Abstract This study compared healthy late-preterm (34–36 week) and healthy full-term (37–41 week) single- ton infants on a range of cognitive, motor, and behavioral outcomes at 2 and 4 years. Eighteen developmental out- comes were analyzed using the Early Childhood Longitu- dinal Survey-Birth Cohort, a nationally representative panel study. Ordinary Least Squares and logistic regres- sions were performed to estimate unadjusted and adjusted differences in developmental outcomes between late- preterm and full-term children. In unadjusted models, late-preterm children scored more poorly than full-term children on most assessments of cognitive ability at 2 and 4 years. After adjusting for demographic, economic, and obstetrical factors, late-preterm children continued to score lower than full-term children on language use at 2 years and on literacy, language, and math at 4 years, but scored at least one standard deviation below the mean on only one of the eighteen outcomes. Late-preterm birth is associated with subtle deficits in cognitive functioning as early as age 2 years. Although the effects may be too small to have clinical relevance, they suggest a trend toward poorer outcomes that have been documented at older ages and suggest that early testing and intervention may enhance the cognitive development of late-preterm children. Keywords Late-preterm Á Child development Á Near-term Á Cognitive outcomes Introduction Late-preterm infants, those born at 34–36 weeks of gesta- tion, accounted for 8.1% of all births in the United States in 2005–2006, up from 6.8% in 1990–1991 [1]. Whereas 69% of all preterm births ( \ 37 weeks) in 1990 were late- preterm, that share increased to 72% in 2005 [2]. While much is known about the subsequent health and develop- ment of infants born before 34 weeks of gestation, rela- tively little is known about how late-preterm infants fare. Most of what is known about the health and develop- ment of late-preterm compared to full-term infants involves relatively short-term outcomes. Late-preterm birth is associated with a number of medical risks and complica- tions during the birth hospitalization, longer neonatal intensive care stays, higher rates of readmission to the hospital after the birth, and higher rates of infant mortality [2–4]. Much less is known about longer-term outcomes associated with late-preterm birth. According to a recent American Academy of Pediatrics Committee Clinical Report, large population studies evaluating long-term neurodevelopmental and behavioral outcomes of late- preterm children are needed [3]. A few recent studies have investigated school age out- comes associated with late-preterm birth. Linnet et al. [5] using Danish registry data to study the association between gestational age and clinically verified hyperkinetic disorder L. Nepomnyaschy (&) School of Social Work, Rutgers, The State University of New Jersey, 536 George St., New Brunswick, NJ 08901, USA e-mail: lennan@ssw.rutgers.edu T. Hegyi Á B. M. Ostfeld Á N. E. Reichman University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ, USA e-mail: hegyith@umdnj.edu B. M. Ostfeld e-mail: ostfelba@umdnj.edu N. E. Reichman e-mail: reichmne@umdnj.edu 123 Matern Child Health J (2012) 16:1612–1624 DOI 10.1007/s10995-011-0853-2