Alcohol consumed by breastfeeding mothers has been associated with reduced grammatical comprehension and cognition in children. This study examined whether drinking or smoking while breastfeeding was associated with reductions in Australian National Assessment Program-Literacy and Numeracy assessments. Data was sourced from The Growing Up in Australia Study. This is an ongoing longitudinal study of 5107 infants and mothers recruited in 2004 and followed over time every two years. Multivariable linear regression found that maternal alcohol consumption at study entry was associated with reductions in Grade 3 (age 7-10 years) National Assessment Program-Literacy and Numeracy writing (b = -1.56, 95% CI: -2.52; -0.60, p = 0.01), spelling (b = -2.06, 95% CI: -3.31; -0.81, p < 0.0001) and grammar and punctuation (b = -2.11, 95% CI: -3.59; -0.64, p = 0.01) scores, as well as Grade 5 (age 9-11 years) spelling scores (b = -1.58, 95% CI: -2.74; -0.43, p = 0.03) in children who had been breastfed at any time. This was not evident in babies who had never breastfed, or in the smaller group of infants who were actively breastfeeding at study entry. Smoking was not associated with any outcome variable. Drinking alcohol while breastfeeding may result in dose-dependent reductions in children's academic abilities. While reductions are small, they may be of clinical significance if mothers drink large quantities. Further analyses are planned to assess developmental, physical and behavioural outcomes in children.
Keywords: academic achievement; alcohol; breastfeeding; cigarettes; drinking; literacy; numeracy; smoking.