Comment on Drinking or Smoking While Breastfeeding and Later Cognition in Children

Several members of our research team read with interest the recent article by Gibson and Porter,¹  entitled “Drinking or Smoking While Breastfeeding and Later Cognition in Children.” The authors suggest that this is the first article to report an association between maternal drinking during the period of breastfeeding and cognitive performance in children aged 6 to 7 years. They found a significant association between “increased or riskier… maternal alcohol consumption” in a child’s first year of life and child cognition as measured by poorer performance on Matrix Reasoning scores at age 6 to 7 years. They concluded that riskier drinking exposes “infants to alcohol through breastmilk [which] may cause dose-dependent reductions in their cognitive abilities.” We agree with these conclusions.

However, this is not the first documented association between alcohol in breast milk and decreased cognitive ability or other negative outcomes in children. Members of our research team published an article in Reproductive Toxicology in 2016 entitled “Breastfeeding and Maternal Alcohol Use: Prevalence and Effects on Child Outcomes and Fetal Alcohol Spectrum Disorders.”²  In this article, we reported a significant association in case control comparisons between postpartum drinkers who breastfed their children and lower IQ in their children at ages 6 to 7 years. We also reported a significantly negative effect on physical growth and development as measured by weight, overall minor anomalies, and the likelihood of a diagnosis on the continuum of fetal alcohol spectrum disorders (FASDs). Controlling for 9 confounders of prenatal risk, including 4 measures of quantity, frequency, and timing of alcohol consumption in the index pregnancies, “mothers who drank postpartum and breastfed their child were 6.4 times more likely to have a child with FASD than breastfeeding mothers who abstained from alcohol while breastfeeding.” Furthermore, after controlling for these confounders, “drinking alcohol during the breastfeeding period independently increased the variance in predicting a FASD diagnosis by 2.5%.” FASD diagnoses require significant deficiencies in neurobehavior and frequently restriction of physical growth and increased dysmorphology.

In our opinion, it is appropriate for the authors to readdress their review of the literature in this article to include in the discussion and conclusions some mention of our work and comparison of the findings from both studies. Although we are gratified that their data and results are clearly supportive of our findings, accuracy and completeness dictate that readers be fully informed of all literature on this topic.