Periconceptional and prenatal tobacco exposure and early externalizing behavior: Developmental pathways through maternal distress and language delay.

Periconceptional and prenatal tobacco exposure (PPTE) has been associated with early externalizing behaviors, yet the developmental pathways underlying this association remain poorly understood. The purpose of this study was to examine potential mechanisms through which PPTE may relate to child behavior. Data were drawn from a prospective, longitudinal cohort of mother-child dyads recruited at birth. The final sample included 203 mothers, predominantly White, with lower income, education, and partnership rates observed among heavier smoking groups. The study collected socio-demographic information and measures of maternal psychological distress, child language ability and behavior. PPTE, defined in this study as a continuous variable representing the average number of cigarettes smoked per day three months prior and during pregnancy, was the primary exposure variable. Maternal psychological distress and child language development were evaluated as potential intervening pathways. A path model was used to evaluate the relative contribution of direct and indirect effects of PPTE on externalizing behavior at 24-months. PPTE significantly predicted both greater maternal psychological distress and poorer child language ability. Both variables were associated with higher externalizing behaviors. In the indirect effects model, the direct effect of PPTE on externalizing behaviors was nonsignificant, while multiple indirect pathways were significant, including via child language development and maternal psychological distress. Findings suggest that the association between PPTE and externalizing behaviors may operate indirectly through maternal psychological distress and child language development.