14 Individualized Fortification of Human Milk: Does it Make the Difference?

Abstract

Background: Inadequate nutrition leading to growth failure is common among premature infants. Although fortified breast milk is the preferred feeding, nutrient intakes achieved with fortified breast milk fall short of meeting nutrient needs consistently. This is mainly due inadequate protein content of fortifiers and high inter- and intra-individual variation in composition of expressed breast milk. Objective: To test a new adjustable fortification regimen designed to ensure that protein needs of premature infants are met all the time. The new regimen encompassed increasing the amount of fortifier and the addition of extra protein to breast milk. These periodic adjustments of fortification were guided by determinations of BUN. The study tested the hypothesis that the new regimen leads to higher protein intake and to improved weight gain compared to standard fortification. Methods: In a prospective, controlled trial, preterm infants with birth weights of 600–1750 grams and gestational ages between 26–34 weeks were fed their own mother's milk, or banked donor milk, or both. Infants were randomly assigned to either the new (adjustable) fortification regimen or the standard regimen. The study period began when feeding volume reached 150 ml/kg/day and ended when infants reached 2000 g. The standard fortification regimen (STD) consisted in the addition of the recommended amount of HMF. The adjustable regimen (ADJ) consisted of standard fortification, but with addition of extra HMF and supplemental protein guided by twice-weekly BUN determinations. Primary outcome was growth, serum biochemical indicators and nutrient intakes were secondary outcomes. Results: Thirty-two infants completed the study as planned (16 ADJ, 16 STD). Infants receiving the ADJ regimen had mean protein intakes of 2.9, 3.2, 3.4 g/kg/d, respectively, in weeks 1, 2 and 3, whereas infants receiving the STD regimen had intakes of 2.9, 2.9, 2.8 g/kg/d, respectively. Infants on the ADJ regimen showed significantly greater gain in weight (17.5 ± 3.0 g/kg/d vs 14.4 ± 3.0 g/kg/d, p<0.01) and greater gain in head circumference (1.4 ± 0.3 vs 1.0 ± 0.3; p<0.05) than infants on the STD regimen. Weight and head circumference gain were significantly correlated with average protein intake (r=0.39, p<0.05 for both). No significant correlations were found between growth parameters and intake of fat and energy. In the ADJ group BUN concentrations increased significantly (p<0.001) over time but were not significantly higher than in the STD group. Conclusion: Premature infants managed with the new adjustable fortification regimen had significantly higher weight and head circumference gains than infants managed with standard fortification. Higher protein intake appears to have been primarily responsible for the improved growth with the adjustable regimen. With the new regimen protein intakes approached intrauterine accretion rates without evidence of metabolic stress. The new fortification method seems to be a promising approach to solving the problem of undernutrition among premature infants fed human milk.