Low birth weight and cognitive outcomes: Evidence for a gradient relationship in an urban, poor, African American birth cohort

This study is one of the first to investigate the relationship between low birth weight and cognitive outcomes in an urban, poor, prospectively designed African-American birth cohort. Multivariate analyses of the Pathways to Adulthood study, a subset of the Johns Hopkins Collaborative Perinatal study, compared low birth weight African-American children with normal birth weight African-American children on the Wechsler Intelligence Scale for Children (WISC) at seven years of age. When controlling for various sociodemographic factors, associations were obtained for the very low birth weight group (less than 2000 g) indicating an overall 7 point IQ difference. Milder associations were reported in the moderately low birth weight (MLBW) group (2000 to 2500 g) resulting in a 3 IQ point decrement compared to a normal birth weight reference group. There were no differential effects for gender. Our study revealed a gradient relationship between low birth weight/preterm birth and cognitive ability. Implications for school psychology prevention, assessment, and intervention are discussed.