Longitudinal Study of Iron Concentration in Korean Preterm Human Milk

Abstract

Purpose: The unique nutrient requirements of premature infants necessitate knowledge of the composition of human milk pro- duced by mothers of such infants. We investigated longitudinal changes in iron concentration of preterm human milk and com- pared to those observed in human milk of mothers of 1-week old term infants to determine optimal iron supplementation guide- lines 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 postpar- tum (36.3±23.1 to 45.8±26.0 μg/dL), but these concentrations were higher than those noted at 1 week in preterm (23.1±14.6 μg/ dL) and term (25.2±7.55 μg/dL) infants. The iron concentration in preterm human milk obtained at corrected term age (42.2±19.4 μg/dL) was significantly higher than that of mature term human milk (25.2±7.55 μg/dL). Conclusion: The concentration of iron in preterm human milk was consistently low during the first 3 months of lactation. Supple- mentation 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).