Title: Frequency and predictors of exposure to maternal alcohol consumption during breastfeeding among children with and without autism
Background: While prenatal alcohol exposure is known to have adverse effects on neurodevelopment, there is little evidence of effects of maternal alcohol consumption during breastfeeding on later child health outcomes, including autism spectrum disorder (ASD).
Methods: The Study to Explore Early Development (SEED) is a case-control study of factors associated with autism and of developmental characteristics and outcomes of autism in multiple sites in the United States, enrolling children between the ages 2.5 and 5 years. Mothers answered a maternal interview at the time of recruitment, including information on alcohol consumption pre-, during, and post-pregnancy. In-person clinic assessments were conducted by research reliable clinicians to confirm autism diagnoses in those with a previous autism diagnosis or screening positive for autism using the Autism Diagnostic Observation Schedule (ADOS). Descriptive statistics were used to convey frequency of and factors associated with maternal alcohol consumption during breastfeeding. Covariate-adjusted logistic regression models were created to explore associations between maternal alcohol consumption and child group classification (ASD, DD, POP).
Results: The percentage of mothers reporting any alcohol consumption during breastfeeding increased across the 3 SEED epochs from 17% in SEED1 to 26% in SEED2 and 36% in SEED3 (p<0.001). The percentage reporting alcohol consumption during the three months pre-pregnancy also increased over time (39% in SEED1; 47% in SEED2; 54% in SEED3 [p<0.001]) while the percentage reporting any alcohol use during pregnancy did not change over time (range 25-26%). Predictors of alcohol consumption during breastfeeding included alcohol consumption pre- and during pregnancy, maternal education, psychiatric disorders, and age. The percentage of mothers reporting alcohol use during breastfeeding was lower in the ASD group (16%) than in the DD group (22%) or the POP group (34%, p<0.001). In adjusted analyses, compared to the POP group, the odds of any maternal alcohol consumption during breastfeeding were significantly lower in the ASD group (adjusted odds ratio [OR] 0.46, 95% confidence interval [CI] 0.39-0.55, p<0.001) and the DD group (OR 0.71, 95% CI 0.61-0.82, p<0.001). Among those reporting any alcohol use during breastfeeding, the average weekly amount was lowest in the ASD group (p<0.001).
Conclusion: Lower alcohol consumption during breastfeeding and pre- and during pregnancy among mothers of children with disabilities relative to controls calls for further research. Reporting biases and confounding factors are important considerations in case-control studies relying on parental report. We note also that the amount of alcohol consumption during breastfeeding reported in this study was low.
