Neiderhiser, J. M., Trentacosta, C. J., Wakschlag, L. S., Leve, L. D., Ganiban, J. M., Shaw, D. S., Natsuaki, M. N., & Reiss, D. (2015). Disentangling the influence of prenatal exposure to cigarettes and postnatal rearing environment on young children’s externalizing trajectories. Manuscript submitted for publication.

Importance: This study addresses the controversy in the field about whether or not maternal smoking during pregnancy has a direct teratogenic effect on emergent psychopathology in children. Clarifying the mechanisms that promote externalizing problems early in development is critical for designing early life preventions.
Objective: To disentangle genetic risk, prenatal exposure to maternal smoking, and postnatal rearing environment on trajectories of externalizing problems in children from 18 to 54 months.
Design: Data from the Early Growth and Development Study, a longitudinal adoption study of parents and offspring, were used. All adoptions were domestic, nonrelative, infant placements (average age at placement = 7 days).
Setting: Population of birth parents and adoptive families completing domestic adoption of infants at birth throughout the United States.
Participants: 561 sets of birth parents, adopted children, and their adoptive parents participated.
Exposures: Maternal smoking during pregnancy was assessed from birth mothers at 4 months postpartum using the Life History Calendar method. Birth mother externalizing psychopathology was assessed at 18 months postpartum using the CIDI and a shortened version of the DIS. Marital hostility was assessed using adoptive parent reports (combined across both parents) at child age 18 months.
Main Outcome Measures: Child externalizing trajectories were assessed using combined parent reports on the Child Behavior Checklist at child ages 18, 27, and 54 months.
Results: We found no main effects of maternal smoking during pregnancy on child externalizing problems intercept or slope. Marital hostility showed a significant interaction with smoking during pregnancy for growth in child externalizing problems, but not intercept. Specifically, SDP × Family Environment on Trajectories of EXT when marital hostility was high, exposed children were more likely to show an increasing trajectory of externalizing problems.
Conclusions and Relevance: The findings from this study indicate that the rearing environment is a critical factor in understanding the impact of maternal smoking during pregnancy on the behavioral outcomes of offspring.