Longitudinal analysis of macronutrients and minerals in human milk produced by mothers of preterm infants.

BACKGROUND & AIMS: The primary objective of this study was to investigate the composition of breast milk of mothers with extremely preterm infants (<28 weeks) for their nutrient content over the first 8 weeks of lactation, and to compare premature to term milk.

METHODS

Breast milk from 102 mothers who had delivered preterm infants and from 10 mothers who had delivered term infants were collected longitudinally. Fat, protein, carbohydrate, minerals and energy content were estimated weekly in each participant. Milk samples were representative of complete 24-h cycles.

RESULTS

Carbohydrate, fat and energy concentrations were significantly higher in preterm than in term milk (p < 0.05). Protein content of both preterm and term milk decreased with the progress of lactation demonstrating significantly higher values in extremely preterm milk (<28 weeks) than in moderately preterm and term milk (p < 0.0001). The sodium levels of preterm milk were significantly elevated (p < 0.05) only in the first week. Other changes in mineral content were detected neither in preterm nor term milk.

CONCLUSIONS

Our data provide new information on the macronutrient content of milk in mothers of extremely preterm infants with possible implications for the nutrition of this population.