Changing Neurodevelopment at 8 Years in Children Born Extremely Preterm Since the 1990s

Abstract

Background and objective: Survival of extremely preterm (EP; <28 weeks' gestation) infants has increased over the last 2 decades. Equivalent reductions in developmental morbidity in early childhood have not been consistently reported. The aim of this study was to determine trends in neurodevelopmental outcomes at 8 years of age of children born EP (22-27 completed weeks' gestation) over the past 2 decades.

Methods: Population-based cohorts of all EP survivors born in the state of Victoria, Australia in 1991-1992, 1997, and 2005 were recruited at birth. At 8 years of age, general intelligence (IQ), academic achievement, and neurosensory status were assessed. Major neurosensory disability was defined as any of moderate or severe cerebral palsy, IQ <-2 SD relative to term controls, blindness, or deafness.

Results: Rates of major neurosensory disability were similar in all eras (1991-1992, 18%; 1997, 15%; 2005, 18%), as were rates of IQ <-2 SD, cerebral palsy, blindness, and deafness. Mean z scores for IQ were similar across eras, but there was some evidence that scores for academic achievement were lower in 2005 than in 1997, and the odds of having academic problems were higher in 2005 than in both earlier eras. These outcomes were not explained by differences in known perinatal care or sociodemographic variables between eras.

Conclusions: Contrary to expectations, rates of major neurosensory disability have not improved, and academic performance is poorer at early school age in 2005 than in earlier eras for EP children born in the state of Victoria, Australia.