Human milk for preterm infants

The term "human milk" conceals important differences between that from an infant's own mother and that obtained from a person or persons who have donated or sold their breast milk. These include differences in nutritional content, and a wide range of non-nutritional components that promote immune, metabolic, and brain development and have evolved over the course of time to transmit biological information from mother to infant. Human milk feeding to preterm babies also encompasses elements such as processing and storage, differences between feeding expressed breast milk versus suckling at the breast, and societal and economic considerations. Current evidence of clinical effectiveness of donated or commercial human milk, and whether macro and micronutrient supplementation are required indicates considerable uncertainty and the possibility of harm. Preterm nutrition is an emotive subject, but important evidence gaps need to be recognised, acknowledged, and addressed if the care of very preterm babies is to improve through a strong evidence-base.