Feeding Infants at the Breast or Feeding Expressed Human Milk: Long-Term Cognitive, Executive Function, and Eating Behavior Outcomes at Age 6 Years.

Abstract

To examine how expressed milk feeding diverges from feeding at the breast in its association with neurodevelopment and behavior. We hypothesized that longer and exclusive feeding at the breast only (ie, no formula, no feeding expressed milk) would be associated with the optimal cognitive developmental, executive function, and eating behaviors and that expressed milk feeding would be associated with less-optimal outcomes. The Moms2Moms cohort (Ohio, US) reported infant feeding practices at 12 months postpartum and children's global cognitive ability, executive function, and eating behaviors at 6 years. Linear and log-binomial regression models estimated associations with durations of feeding at the breast, expressed milk, human milk (modes combined), and formula. Among 285 participants, each month of exclusive feeding at the breast only was associated with a decreased risk of clinically meaningful executive function (working memory) deficit (adjusted relative risk [RR] 0.78, 95% CI 0.63-0.96) but was unassociated with inhibition (adjusted RR 0.92, 95% CI 0.85-1.01). Feeding expressed milk was not clearly related to executive function outcomes. No associations with global cognitive ability were observed. Weak associations were observed with eating behaviors for some feeding practices. Feeding at the breast may offer advantages to some aspects of executive function that expressed milk may not. Large, prospective studies exploring mechanisms could further distinguish the effect of feeding mode from that of nutrients.