Breast-fed babies gain less weight than those fed by bottle, even if mostly expressed breast milk is used, conclude US researchers.
The longitudinal study investigated1,900 infants born after 35 weeks' gestation with a birth weight of at least 2.25kg. Mothers reported their feeding patterns and infant's weight gain at three, five, seven and 12 months on a questionnaire.
Weight gain was negatively associated with the proportion of breast milk feedings, but it was positively associated with the proportion of bottle feedings among those who used mostly breast milk.
Compared with infants exclusively fed by breast, using a bottle was associated with weight gain of 71 or 89g more per month in those using non-human or human milk, respectively.
Infants fed using a combination of expressed human milk and nonhuman milk, gained only 37g more than infants fed at the breast.
Study lead Dr Ruowei Li, medical epidemiologist at the Centers for Disease Control and Prevention in Atlanta, concluded breast milk should be first choice to prevent future obesity in children.
She said: ‘Regardless of milk type in the bottle, bottle-feeding might be distinct from breastfeeding in its effect on infant weight gain. Feeding at the breast needs to be the first choice for babies.'