Motor and cognitive outcomes in nondisabled low-birth-weight adolescents: early determinants.

OBJECTIVES: To describe motor and cognitive outcomes in nondisabled low-birth-weight (LBW) adolescents and to determine the relation of specific prenatal, perinatal, and neonatal risk factors to these outcomes. DESIGN: A prospective epidemiological study. SETTING: An adolescent follow-up of a regional LBW (<2000 g) cohort born in or admitted to 3 hospitals between September 1, 1984, and June 30, 1987 (n = 1105). Of 862 eligible survivors, 628 (72.9%) underwent assessment at a mean age of 16 years; of these, 33 had severe disability that precluded psychometric evaluation. The 474 nondisabled adolescents undergoing assessment at home had slightly less social risk at birth than did all other nondisabled eligible adolescents. PARTICIPANTS: The 474 nondisabled LBW adolescents assessed at home. Main Exposures Basic birth characteristics (social risk, sex, fetal growth ratio, and gestational age), neonatal cranial ultrasound abnormalities, and other early medical complications. MAIN OUTCOME MEASURES: Riley Motor Problems Inventory and Wechsler Abbreviated Scales of Intelligence. RESULTS: Nondisabled LBW adolescents had an excess of motor problems compared with the normative sample. The IQ scores, although within the normal range, were significantly lower than population norms. Independent predictors of total motor problems included male sex, white matter injury on neonatal ultrasound, and days of ventilation. Independent predictors of lower Full Scale IQ scores included social disadvantage, fetal growth ratio, and white matter injury on neonatal ultrasound. CONCLUSIONS: Specific prenatal, perinatal, and neonatal risk factors influence motor and cognitive performance in nondisabled LBW survivors well into adolescence, even when controlling for social risk. Advances in maternal-fetal and neonatal care can substantially improve these long-term outcomes.

Special education services and school performance in a regional cohort of low-birthweight infants at age nine.

Previous research has shown that low birthweight is a predictor of several adverse educational outcomes, including special educational placement, by middle school age. Most low-birthweight follow-up studies that have extended to school age have focused on very small infants-- < 1500 or < 1000 g; less is known of the school age outcomes for infants with only moderately low birthweight (1500-2000 g). This study examines the prevalence of special educational placement and the relationship of such placement to grade retention, verbal and performance scores on tests of general intelligence, reading and maths achievement scores and classroom hyperactivity among low-birthweight children. In a regional birth cohort of 1105 infants born between 1984 and 1987 and weighing 500-2000 g, 868 children were available for follow-up at age nine. Information on special education placement as well as grade retention, intelligence, academic achievement and classroom behaviour was available on 645 (74% completion rate). Nearly a third of the cohort was classified as needing special education. Special education placement followed a birthweight gradient, occurring among 29.3% of children with birthweights 1500-2000 g, among 32.5% in children 1000-1500 g and 49.4% in children < 1000 g. Among children in special education, a similar birthweight gradient was found for maths achievement and hyperactivity, but not for reading achievement or IQ scores. Among children not in special education, only maths achievement showed such a decline with birthweight. A substantial proportion of low-birthweight children, including those of moderate low birthweight, receive special education services, although the need is greatest among those with the lowest birthweights. Maths achievement declined with birthweight regardless of educational placement. The medical and social risk factors that accompany low birthweight and may account for these findings, require further study.