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.
To determine the cognitive, educational, and behavioral outcome of ELBW
or very preterm infants born in the 1990s compared with normal birth weight
Regional cohort study.
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.
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.
School-aged ELBW or very preterm children born in the 1990s continue
to display cognitive, educational, and behavioral impairments.