RESUMO
OBJECTIVE: To determine if iron supplementation of 2 mg/kg per day, in addition to routine iron-fortified formula or mother's milk, increased the hematocrit (Hct) at 36 weeks' postmenstrual age (PMA). METHODS: : Infants with a birth weight <1500 g who reached 120 mL/kg per day of feedings before 32 weeks' PMA were randomly assigned to iron (multivitamin with iron) or control (multivitamin) from enrollment until 36 weeks' PMA (or discharge, if sooner). Investigators and caregivers were masked. Transfusion guidelines were used. The primary outcome was Hct at 36 weeks' PMA. A nonparametric rank sum analysis was performed so that infants who died before 36 weeks and infants who were transfused could be included in an intention-to-treat analysis. Infants were ranked by death (lowest rank) then by number of transfusions (next lowest ranks). For infants who survived and were not transfused, the 36-week PMA Hct was used for the rank. RESULTS: One hundred fifty infants were enrolled (76 iron, 74 controls). There were 2 deaths (1 in each group). One hundred other infants (47 iron, 53 controls) received transfusion(s). There was no significant difference in the primary outcome ranking (P = .59), in the number of transfusions per subject (P = .64), or in 36-week Hct (iron mean ± SD, 29.2% ± 4.0%; control, 28.3% ± 4.5%; mean difference and 95% confidence interval 0.9 [-0.5 to 2.3]; P = .21) or reticulocyte count among survivors. No short-term adverse effects of iron supplementation were observed. CONCLUSIONS: Among infants <1500 g birth weight, iron supplementation, in addition to routine iron intake, did not significantly increase the 36-week Hct or the decrease number of transfusions.