Breast-Feeding and IQ at 5 Years

Human milk contains more of the fatty acids needed for brain development than infant formula. To estimate how breast-feeding relates to cognitive function at age 5, researchers conducted a secondary analysis of two trials that rigorously evaluated child IQ in women with prenatal subclinical hypothyroidism or hypothyroxinemia but not overt thyroid disease.

The secondary study included 772 women with breast-feeding data whose children did not have anomalies and did not require neonatal intensive care; 614 women reported any amount of breast-feeding. In analyses adjusting for maternal education and health insurance, 5-year-olds who were ever breast-fed were less likely to have IQ scores below 85 (adjusted odds ratio, 0.62). Each month of breast…