A comparison of oral and intravenous iron supplementation in preterm infants receiving recombinant erythropoietin.

To determine whether intravenously administered iron supplements would improve the hematologic response to recombinant erythropoietin in stable preterm infants. Forty-two preterm infants (<33 weeks' gestation, birth weight < 1500 gm, hematocrit <38%) were treated with recombinant human erythropoietin (Eprex), 600 U/kg per week, and randomly assigned to receive either an oral preparation of ferrous lactate (elemental iron, 12 mg/kg per day) or an intravenous preparation of iron sucrose (6 mg/kg per week). Hematocrits, reticulocyte counts, and transfusions were similar in the oral group (OG) and the intravenous group (IVG). However, markedly higher serum ferritin concentrations were noted in the IVG (p <0.001), and by completion of the study the arithmetic mean values were 265 +/- 127 microg/L versus 137 +/- 65 microg/L in the IVG and the OG, respectively. The numbers of hypochromic erythrocytes increased in both groups during the study but were significantly higher in the OG (p = 0.04). Mean daily weight gain in the IVG (27 +/- 6.4 gm/day) was greater than in the OG (22.9 +/- 4.78 gm/day; p = 0.04). High doses of both orally administered iron and intravenously administered iron sucrose appear to supply sufficient iron for erythropoiesis in stable infants. Storage iron may become depleted after oral supplementation. The intravenous preparation appears to be safe and maintains serum ferritin concentrations, and it may be indicated for patients with low ferritin levels and for those not established on enteral feedings.