Pre-discharge iron status and its determinants in premature infants

Abstract

Objective: To evaluate pre-discharge iron status and identify its determinants in infants’ ≤ 32 weeks gestational age (GA). Methods: In a prospective observational study, 24–32 weeks GA infants who did not meet exclusion criteria: congenital viral infections, chromosomal disorders, or cranio-facial anomalies were eligible. Iron status was evaluated by measuring serum ferritin (SF) at 35 weeks post-menstrual age (PMA). Infants with infection or elevated C-reactive protein within 10 days prior to evaluation of iron status were excluded. Results: Of 131 infants studied, 23% had latent iron deficiency (SF < 76 ng/ml), 58% had normal iron status (75–400 ng/ml), and 19% had iron overload (SF > 400 ng/ml). On bivariate analysis, preeclampsia, GA, birth weight, patent ductus arteriosus, prior erythrocyte transfusion, phlebotomy loss, and chronic lung disease were associated with iron status. On ordered logistic regression, prior erythrocyte transfusion (frequency [OR 1.41, 95% CI:1.2–1.6] or cumulative amount [OR 1.03, 95% CI:1.02–1.04]) or net erythrocyte balance (amount of erythrocyte transfusion minus phlebotomy loss; OR 1.04, 95% CI:1.02–1.05) was significantly associated with iron status. Among infants who received > three erythrocyte transfusions, 50% developed iron overload. Conclusions: Iron status at 35 weeks PMA is extremely variable and is predicted by prior erythrocyte transfusions or net erythrocyte balance in premature infants.

Keywords::

• Latent iron deficiency
• iron overload
• neonates
• brain development

Acknowledgement

We are grateful to Erica Burnell, research coordinator, for data collection. We are also grateful to Hongyue Wang, Ph.D., a biostatistician, for her help and guidance.

Declaration of Interest: The research was supported by Grant Number UL1 RR 024160 from the National Center for Research Resources.