Survival and major neurodevelopmental impairment in extremely low gestational age newborns born 1990-2000: A retrospective cohort study

Background: It is important to determine if rates of survival and major neurodevelopmental impairment in extremely low gestational age newborns (ELGANs; infants born at 23-27 weeks gestation) are changing over time. Methods: Study infants were born at 23 to 27 weeks of gestation without congenital anomalies at a tertiary medical center between July 1, 1990 and June 30, 2000, to mothers residing in a thirteen-county region in North Carolina. Outcomes at one year adjusted age were compared for two epochs of birth: epoch 1, July 1, 1990 to June 30, 1995; epoch 2, July 1, 1995 to June 30, 2000. Major neurodevelopmental impairment was defined as cerebral palsy, Bayley Scales of Infant Development Mental Developmental Index more than two standard deviations below the mean, or blindness. Results: Survival of ELGANs, as a percentage of live births, was 67% [95% confidence interval: (61, 72)] in epoch 1 and 71% (65, 75) in epoch 2. Major neurodevelopmental impairment was present in 20% (15, 27) of survivors in epoch 1 and 14% (10, 20) in epoch 2. When adjusted for gestational age, survival increased [odds ratio 1.5 (1.0, 2.2), p = .03] and major neurodevelopmental impairment decreased [odds ratio 0.54 (0.31, 0.93), p = .02] from epoch 1 to epoch 2. Conclusion: The probability of survival increased while that of major neurodevelopmental impairment decreased during the 1990's in this regionally based sample of ELGANs.