Feeding strategies for premature infants: Beneficial outcomes of feeding fortified human milk versus preterm formula

Background. In a large-scale study of feeding strategies in premature infan ts (early vs later initiation of enteral feeding, continuous vs bolus tube- feeding, and human milk vs formula), the feeding of human milk had more eff ect on the outcomes measured than any other strategy studied. Therefore, th is report describes the growth, nutritional status, feeding tolerance, and health of participating premature infants who were fed fortified human milk (FHM) in comparison with those who were fed exclusively preterm formula (P F). Methods. Premature infants were assigned randomly in a balanced two-way des ign to early (gastrointestinal priming for 10 days) versus late initiation of feeding (total parenteral nutrition only) and continuous infusion versus intermittent bolus tube-feeding groups. The type of milk was determined by parental choice and infants to receive their mother's milk were randomized separately from those to receive formula. The duration of the study spanne d the entire hospitalization of the infant. To evaluate human milk versus f ormula feeding, we compared outcomes of infants fed >50 mL.kg(-1).day(-1) o f any human milk (averaged throughout the hospitalization) with those of in fants fed exclusively PF. Growth, feeding tolerance, and health status were measured daily. Serum indices of nutritional status were measured serially , and 72-hour nutrient balance studies were conducted at 6 and 9 weeks post natally. Results. A total of 108 infants were fed either >50 mL.kg(-1).day(-1) human milk (FHM, n = 62) or exclusively PF (n = 46). Gestational age (28 +/- 1 w eeks each), birth weight (1.07 +/- 0.17 vs 1.04 +/- 0.19 kg), birth length and head circumference, and distribution among feeding strategies were simi lar between groups. Infants fed FHM were discharged earlier (73 +/- 19 vs 8 8 +/- 47 days) despite significantly slower rates of weight gain (22 +/- 7 vs 26 +/- 6 g.kg(-1).day(-1)), length increment (0.8 +/- 0.3 vs 1.0 +/- 0.3 cm week-l), and increment in the sum of five skinfold measurements (0.86 /- 0.40 vs 1.23 +/- 0.42 mm.week(-1)) than infants fed PF. The incidence of necrotizing enterocolitis and late-onset sepsis was less in the FHM group. Overall, there were no differences in any measure of feeding tolerance bet ween groups. Milk intakes of infants fed FHM were significantly greater tha n those fed PF (180 +/- 13 vs 157 +/- 10 mL.kg(-1).day(-1)). The intakes of nitrogen and copper were higher and magnesium and zinc were lower in group FHM versus PF. Fat and energy absorption were lower and phosphorus, zinc, and copper absorption were higher in group FHM versus PF. The postnatal ret ention (balance) surpassed the intrauterine accretion rate of nitrogen, pho sphorus, magnesium, zinc, and copper in the FHM group, and of nitrogen, mag nesium, and copper in the PF group. Conclusions. Although the study does not allow a comparison of FHM with unf ortified human milk, the data suggest that the unique properties of human m ilk promote an improved host defense and gastrointestinal function compared with the feeding of formula. The benefits of improved health (less sepsis and necrotizing enterocolitis) associated with the feeding of FHM outweighe d the slower rate of growth observed, suggesting that the feeding of FHM sh ould be promoted actively in premature infants.