Maternal alcohol use during pregnancy and offspring trajectories of height and weight: A prospective cohort study

Background: Previous studies have examined associations between alcohol use in pregnancy and offspring birth size but evidence on whether associations persist during childhood is limited. Methods: We examined the association between maternal drinking during pregnancy and trajectories of offspring weight and height from 0 to 10 years in 7597 mother-child pairs in the Avon Longitudinal Study of Parents and Children. To strengthen the inference, we compared the maternal alcohol-offspring growth association with the partner alcohol-offspring growth association, to partially control for unmeasured confounding. We also performed sensitivity analyses restricting our analysis to women of white ethnicity and participants with three or more growth measures. Results: Maternal occasional or light daily drinking during pregnancy was not associated with reduced birth weight, birth length or offspring growth trajectories up to age 10 years. The infants of heavy drinking mothers were born 0.78. cm shorter (95% CI -1.34, -0.22) and 0.22. kg lighter (95% CI -0.34, -0.09) than infants of pregnancy abstainers but by age 10, offspring of heavy drinking mothers were of comparable height (mean difference 0.59. cm, 95% CI -0.93, 2.11) and weight (mean difference 0.41. kg, 95% CI -0.70, 1.52). These associations were not observed for heavy partner drinking and were not altered in sensitivity analyses. Conclusion: Maternal occasional or light daily drinking is not associated with birth weight, birth length or postnatal growth, but residual confounding may persist. Maternal heavy drinking may have an intrauterine association with reduced birth weight and length but this association is overcome during childhood.