Energy expenditure for breastfeeding and bottle-feeding preterm infants

OBJECTIVE: We hypothesized that resting energy expenditure (REE) would be higher after breastfeeding than after bottle-feeding. METHODS: Nineteen preterm infants (gestational age: 32 weeks) in stable condition who were nourished entirely with their mothers' breast milk were assigned randomly to feeding either by bottle or at the breast. Each infant served as his or her own control subject. REE was measured for 20 minutes after feeding. Breast milk quantity was evaluated with prefeeding and postfeeding weighing. REE values for bottle-feeding and breastfeeding were compared with paired t tests. RESULTS: Contrary to our null hypothesis, the group's mean REE values after bottle-feeding and breastfeeding were very similar (284.7 ± 26.8 kJ/kg per day [68.3 ± 6.4 kcal/kg per day] vs 282.6 ± 28.5 kJ/kg per day [67.5 ± 6.8 kcal/kg per day]; not significant). The duration of feeding was significantly longer for breastfeeding than for bottle-feeding (20.1 ± 7.9 vs 7.8 ± 2.9 minutes; P < .0001). CONCLUSION: There was no significant difference in REE when infants were breastfed versus bottle-fed. Longer feeding times at the breast did not increase REE. We speculate that it is safe to recommend feeding at the breast for infants born at >32 weeks when they can tolerate oral feeding.