Birthweight and Child Outcomes
1
Low Birth Weight and Children's Cognitive Development and Behavior:
Evidence from the ECLS-K
Abstract
Using data from the Early Childhood Longitudinal Kindergarten Cohort (ECLS-K), we assess the
relationship between low birthweight (LBW 15001-2500g) and very low birthweight status (VLBW
<1500) on a variety of childhood developmental outcomes including (1) academic ratings scales, (2)
social ratings scales, (3) motor skills, (4) grade failure, (5) self-reported scales and (6) objective math
and reading scores. (1) At kindergarten entry LBW and VLBW children are rated lower on academic
rating scales, but these scores were no longer significant after controlling for background
characteristics. (2) VLBW children displayed disadvantages in Social Rating Scales, especially in
approaches to learning. (3) LBW and VLBW children have significantly lower levels of motor skills
and (4) after controlling for all covariates, there is no evidence that LBW children are more likely to
repeat grades. Finally, (5) at kindergarten entry, LBW show significantly lower math scores, although
there are no differences in growth rates, in either math or reading. The evidence from this study
suggests that although LBW children tend to have lower performance, most of the difference between
those children and normal children are due to other associated disparities.
Introduction
As an international marker of infant health that is the second highest predictor of infant
mortality, low birth weight (LBW) status is an important indicator of child well-being (UNICEF
2006; Hummer 1993). Children in the United States are at higher risk of being born LBW than in
almost any other developed country and the risk varies dramatically by race (Matthews et al. 2003).
African American women’s risk of giving birth to a LBW child is twice that of white women and
with Hispanic women overall having similar rates to white women (Reichman 2005). Although
much of the research exploring the determinants of LBW and its ties to infant mortality has been
well-established there is a growing literature among social demographers assessing the impact of
LBW on child developmental outcomes.
While several longitudinal studies have explored LBW (<2500g) and VLBW (<1500g) as a
predictor of developmental outcomes, both cognitive and behavioral, there has yet to be consensus
on the magnitude of the LBW impact on child developmental outcomes controlling for family
circumstances and other contextual factors that are highly associated with both child well-being and
risk for LBW. Factors associated with LBW as well as child cognitive and behavioral development
include family poverty status, maternal education, maternal age, family structure, and neighborhood
characteristics (Gephart 1997; Duncan and Brooks-Gunn 1997). Because racial and economic
disparities continue to pervade U.S. society, the potential impact of children being LBW could
potentially exacerbate the already existing differences in developmental outcomes reported in the
larger developmental literature. An improved understanding of the relative contribution of LBW
Page 1 of 20 
Convention