ABSTRACT
PURPOSE: The unique nutrient requirements of premature infants necessitate knowledge of the composition of human milk produced by mothers of such infants. We investigated longitudinal changes in iron concentration of preterm human milk and compared to those observed in human milk of mothers of 1-week old term infants to determine optimal iron supplementation guidelines when preterm infants are nourished exclusively by breast feeding. METHODS: Human milk samples were collected at 1, 2, 4, 6, 8 and 12 weeks postpartum from 103 mothers who delivered infants of gestational age <34 weeks or weighing <1,800 g. Term human milk samples were collected at 1 week postpartum from 24 mothers. RESULTS: There were no significant differences in the iron concentrations of preterm human milk obtained at 2 to 8 weeks postpartum (36.3+/-23.1 to 45.8+/-26.0 microg/dL), but these concentrations were higher than those noted at 1 week in preterm (23.1+/-14.6 microg/dL) and term (25.2+/-7.55 microg/dL) infants. The iron concentration in preterm human milk obtained at corrected term age (42.2+/-19.4 microg/dL) was significantly higher than that of mature term human milk (25.2+/-7.55 microg/dL). CONCLUSION: The concentration of iron in preterm human milk was consistently low during the first 3 months of lactation. Supplementation with iron of at least 2 mg/kg/day should be considered for preterm infants who are exclusively breastfed and who have low body iron stores, to meet the minimum enteral iron requirements recommended by AAP-CON (2004).