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Infants Born One to Three Weeks Early at Risk of Developmental Delay


Until recently, infants born one to three weeks early – called “late preterm” – have received little attention because of assumptions that they had little risk of long-term problems. But a new study shows that those last weeks in the womb, when dramatic brain maturation and growth occur, are associated with the child’s future development and success in school. In “Early School-Age Outcomes of Late Preterm Infants,” researchers found healthy children born at 34 to 36 weeks’ gestation had a 36 percent higher risk of developmental delay or disability through the first five years of life compared with healthy term infants (born at 37 to 41 weeks’ gestation). 

Researchers found late preterm infants were more likely to be suspended in kindergarten or held back in kindergarten. These infants represent a significant portion of preterm deliveries in the U.S. It has been estimated that 70 percent of preterm births are born at 34 to 36 weeks’ gestation. In addition, births at 34 to 36 weeks’ gestation increased 25 percent between 1990 and 2005, whereas births at less than 34 weeks’ gestation remained unchanged. The study authors suggest obstetricians should consider the risk for developmental delay when weighing the risks and benefits of late preterm delivery. These children need close developmental follow-up, and parents and physicians should be aware of the risks for school underachievement and behavioral problems so they can get prompt referrals to early intervention services if needed.


The American Academy of Pediatrics is an organization of 60,000 primary care pediatricians, pediatric medical subspecialists and pediatric surgical specialists dedicated to the health, safety and well-being of infants, children, adolescents and young adults. For more information, visit