Human milk, fortification and preterm nutrition

Overview & Definition

Preterm enteral nutrition is the discipline of delivering energy, protein, minerals, and micronutrients after birth at rates that can support growth approaching foetal accretion. ESPGHAN 2010 stated that the preferred food for premature infants is fortified human milk from the infant's own mother, or alternatively preterm formula, and framed advisable ranges for stable-growing infants up to approximately 1800 g ^[6]. ESPGHAN 2022 updates the numeric targets for infants with birthweight under 1800 g: a reasonable total energy intake of 115 to 140 kcal/kg/day (GOR A) and at least 3.5 to 4.0 g protein/kg/day, with protein increasable to 4.5 g/kg/day if growth is slow and other nutrients are adequate (GOR A) ^[11].

Unfortified human milk cannot meet those protein targets. ESPGHAN 2022 notes that human milk protein is variable at about 1 g/100 mL, falling from around 1.5 to 2.0 g/dL before two weeks to 1.0 to 1.5 g/dL thereafter, while donor milk contains around 0.9 to 1.0 g/dL or less ^[11]. At 150 mL/kg/day that is roughly 1.4 to 1.5 g/kg/day of protein from mature milk — well below 3.5 to 4.0 g/kg/day — which is why multicomponent fortification is routine ^[11].

Embleton 2001 showed that recommended intakes of 120 kcal/kg/day and 3 g/kg/day protein were rarely achieved early, producing cumulative energy and protein deficits and falling z-scores (week-5 z-scores −1.14 versus −0.82 for infants at or under 30 weeks versus at or after 31 weeks); dietary intake accounted for 45 percent of z-score variation ^[1]. Ehrenkranz 1999 constructed VLBW postnatal curves: after birth weight was regained, weight gain of 14.4 to 16.1 g/kg/day approximated intrauterine rates, yet most infants born at 24 to 29 weeks had not achieved the median birth weight of the reference fetus at the same postmenstrual age by discharge ^[2].

References11ShowHide

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3. [3]Quigley M, Embleton ND, McGuire W Formula versus donor breast milk for feeding preterm or low birth weight infants Cochrane Database Syst Rev, 2019.PMID 31322731
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10. [10]Fusch S, Fusch G, Yousuf EI, et al Individualized Target Fortification of Breast Milk: Optimizing Macronutrient Content Using Different Fortifiers and Approaches Front Nutr, 2021.PMID 34621769
11. [11]Embleton ND, Jennifer Moltu S, Lapillonne A, et al. Enteral Nutrition in Preterm Infants (2022): A Position Paper From the ESPGHAN Committee on Nutrition and Invited Experts J Pediatr Gastroenterol Nutr, 2023.PMID 36705703