Iron stores in low and normal birth weight infants at birth and in early infancy.

Serum ferritin levels of low birth weight (LBW; BW < 2,500 g) and normal birth weight (NBW; BW ≥ 2,500 g) infants were evaluated at birth and at 3 mo using electrochemiluminescence immunoassay. At birth, levels were 318.6 (31.0-829.5) ng/mL in LBW (n = 217) and 366.2 (122.4-858.5) ng/mL in NBW infants (n = 116; p < 0.01), with 1.4 % of LBW and none of the NBW infants having levels <12 ng/mL (p = 0.20). At follow up, levels were 66.9 (4.5-567.7) ng/mL in LBW (n = 126) and 126.2 (6.8-553.7) ng/mL in NBW infants (n = 76; p = 0.27), with 11.9 % of LBW and 11.8 % of NBW infants having levels <12 ng/mL (p = 0.80).