Neurodevelopmental outcomes of extremely preterm infants.

Survival of extremely preterm infants has improved since 2000. Neurodevelopmental impairment rates remain high at the limits of viability. Although improved survival and neurodevelopmental impairment rates are associated with higher gestational age and more recent year of birth, significant variability in findings among geographic areas and networks is evident, and seems related to differences in population, management style, regional protocols, definitions, and outcome assessments. Outcome studies during adolescence and young adult age are needed to determine the long-term impact of extremely preterm birth.