Aim This nonsystematic review examined differences in the composition of raw maternal breastmilk and pasteurised donor milk and possible health effects on preterm infants. Methods We searched PubMed up to July 2018 for studies published in English that focused on four comparisons as follows: raw maternal milk versus donor milk, human milk before and after Holder pasteurisation, milk from mothers who delivered preterm and at term and milk collected during early and late lactation. We also searched for possible effects of the milk components, as well as the effects of maternal and donor milk on preterm infants’ health. Results Raw maternal milk contained factors involved in antioxidant and anti‐inflammatory defence, gut microbiome establishment and the maturation of immune defences, food tolerability and metabolism. Many of these factors were reduced or abolished in processed donor milk. Both maternal milk and donor milk have been associated with a reduced incidence of necrotising enterocolitis. High‐dose feeding with maternal milk during the neonatal period reportedly reduced the risk of other morbidities and promoted growth and neurodevelopment. Conclusion Many of the components in raw maternal breastmilk were lacking in pasteurised donor milk, which was inferior in promoting the growth and development of very preterm infants.

Preterm infants are at increased risk of extrauterine growth restriction, which at least in part is caused by very high extrauterine nutritional needs. 1 In addition, the inability to assimilate sufficient nutrition due to feeding intolerance secondary to immaturity and neonatal morbidities is especially common in extremely preterm infants. The result is significant energy and protein deficits, primarily in the early postnatal period. 2 Most extremely preterm neonates suffer from growth restriction that can persist into childhood. 3

Purpose Choline is an essential nutrient for fetal and infant growth and development. Parenteral nutrition used in neonatal care lack free choline but contain small amounts of lipid-bound choline in the form of phosphatidylcholine (PC). Here, we examined the longitudinal development of serum free choline and metabolically related compounds betaine and methionine in extremely preterm infants and how the concentrations were affected by the proportion of parenteral fluids the infants received during the first 28 postnatal days (PNDs). Methods This prospective study included 87 infants born at gestational age (GA) < 28 weeks. Infant serum samples were collected PND 1, 7, 14, and 28, and at postmenstrual age (PMA) 32, 36, and 40 weeks. The serum concentrations of free choline, betaine, and methionine were determined by 1H NMR spectroscopy. Results The median (25th–75th percentile) serum concentrations of free choline, betaine, and methionine were 33.7 (26.2–41.2), 71.2 (53.2–100.8), and 25.6 (16.4–35.3) µM, respectively, at PND 1. The choline concentration decreased rapidly between PND one and PND seven [18.4 (14.1–26.4) µM], and then increased over the next 90 days, though never reaching PND one levels. There was a negative correlation between a high intake of parenteral fluids and serum-free choline. Conclusion Circulating free choline in extremely preterm infants is negatively affected by the proportion of parenteral fluids administered. Trial registration ClinicalTrials.gov Identifier NCT02760472, April 29, 2016, retrospectively registered.