Studies have shown that maternal obesity affects breast milk quantity and quality, while any breast milk exposure contributes to early cognitive development. Yet, the extent to which maternal obesity, breast milk quantity, and breast milk quality foster this process in infants is unclear. The aim of this study was to determine whether maternal weight status, feedings/day, and feeding composition in the form of human milk oligosaccharides (HMOs) predicted infant cognitive development at 24 months.


Participants were 50 Hispanic mother-infant pairs. Maternal pre-pregnancy BMI was reported. Breast milk was collected at 1 and 6 months, and feedings/day were recorded. HMO composition was analyzed using high-pressure liquid chromatography. Secretor status was determined by presence or near absence of HMOs 2’-fucosyllactose (2’FL) or lacto-N-fucopentaose I. Infant cognitive development score was assessed with Bayley-III at 24 months. Hierarchical linear regression models for infant cognitive development score were used, adjusting for maternal age, secretor status, infant age, sex, and birthweight.


Maternal pre-pregnancy BMI was not related to feedings/day or HMO composition; however, it predicted lesser infant cognitive development score (β= -0.34, P=0.02). Feedings/day (β= 0.34) and HMO 2’FL (β= 0.61) at 1 month predicted greater infant cognitive development score (both P≤0.02). The relationship between feedings/day and greater infant cognitive development score was no longer significant after further adjustment for 2’FL, which remained significant. Feedings/day and 2’FL at 6 months were not related to infant cognitive development score.


Our data suggest that mothers inform early cognitive development through multiple means. While maternal weight status may be a separate negative influence, greater breast milk feedings at 1 month contributed to infant cognitive development, and this was explained by greater exposure to HMO 2’FL at 1 month.