Neurobehavioral outcomes of school-age children born extremely low birth weight or very preterm in the 1990s

Abstract

Context: The outcome into school age of regional cohorts of children born in the 1990s with birth weights less than 1000 g (extremely low birth weight, ELBW) or earlier than 28 weeks' gestation (very preterm) is not known.

Objective: To determine the cognitive, educational, and behavioral outcome of ELBW or very preterm infants born in the 1990s compared with normal birth weight (NBW) controls.

Design: Regional cohort study.

Setting: Victoria, Australia.

Participants: The ELBW or very preterm cohort was composed of 298 consecutive survivors born during 1991-1992. The NBW cohort was composed of 262 randomly selected children with birth weights of more than 2499 g.

Main outcome measures: Cognitive ability, educational progress, and behavioral problems.

Results: The follow-up rates from birth to 8 years of age for survivors were 92.3% (275/298) for the ELBW or very preterm cohort and 85.1% (223/262) for the NBW cohort. The ELBW or very preterm children scored significantly below NBW controls on full-scale IQ (mean difference, -9.4; 95% confidence interval [CI], -12.1 to -6.7; P<.001) and indices of verbal comprehension (mean difference, -6.8; 95% CI, -9.5 to -4.2; P<.001), perceptual organization (mean difference, -9.9; 95% CI, -12.7 to -7.2; P<.001), freedom from distractibility (mean difference, -8.1; 95% CI, -10.8 to -5.5; P<.001), and processing speed (mean difference, -6.7; 95% CI, -9.4 to -4.0; P<.001). The ELBW or very preterm children performed significantly worse than the NBW cohort on tests of reading (mean difference, -6.7; 95% CI, -9.5 to -3.9; P<.001), spelling (mean difference, -5.6; 95% CI, -8.0 to -3.3; P<.001), and arithmetic (mean difference, -8.8; 95% CI, -11.3 to -6.2; P<.001). Attentional difficulties, internalizing behavior problems, and immature adaptive skills were more prevalent in the ELBW or very preterm cohort.

Conclusion: School-aged ELBW or very preterm children born in the 1990s continue to display cognitive, educational, and behavioral impairments.