Fetal growth and neurobehavioral outcomes in childhood

- Although there is evidence from prior studies that low birth weight is associated with lower cognitive test scores, the body of research focusing on the effect of birth weight on non-cognitive outcomes, such as neurobehavioral outcomes, is more limited.
- Using national, longitudinal, survey data on children from the US, we find that poor fetal growth is associated with increased risk of lifetime diagnosis of developmental delay and speech impairment.
- We also find that poor fetal growth is associated with an index of behavior problems reported by mothers. In particular, the fetal growth rate is negatively associated with disruptive behaviors such as antisocial, oppositional, and hyperactive behaviors among boys.

Using a sample of sibling pairs from a nationally representative U.S. survey, we examine the effects of the fetal growth rate on a set of neurobehavioral outcomes in childhood measured by parent-reported diagnosed developmental disabilities and behavior problems. Based on models that include mother fixed effects, we find that the fetal growth rate, a marker for the fetal environment, is negatively associated with lifetime diagnosis of developmental delay. We also find that the fetal growth rate is negatively associated with disruptive behaviors among male children. These results suggest that developmental disabilities and problem behaviors may play a role in explaining the well-documented association between birth weight and human capital outcomes measured in adulthood.