O2067: Are very low birth weight infants iron deficient at birth

Background: Iron deficiency (ID) is common in neonatal population and is associated with adverse neurodevelopmental impairment. Premature infants are at high risk for ID and up to 17% of premature infants are ID at birth. Hence it is crucial to identify and treat ID in the immediate neonatal period. Serum ferritin and transferrin saturation (TS) are commonly used to diagnose ID. However, ferritin is an acute phase reactant and increased with infection or inflammation and TS has diurnal variation. Currently, there are no standardized guidelines for diagnosing ID in neonatal population. Reticulocyte hemoglobin content (Ret-He) is an early indicator of ID and is recommended by AAP as a screening tool for ID. We aim to determine the incidence of ID in very low birth (VLBW) infants at birth as evidenced by low Ret-He and abnormal iron studies.

Methods: This is a retrospective chart review of all VLBW infants born between 10/2021 and 01/2024. The data on complete blood count (CBC) and reticulocyte studies performed during first few days of life were collected from medical records. Low Ret-He is defined as ≤29pg. All infants with Ret-He ≤29 had following iron studies performed based on our unit protocol- serum iron, transferrin saturation (TS) and ferritin. Infants with low Ret-He were compared with those with normal Ret-HE. Iron deficiency is defined as serum iron < 100 mcg/dL, transferrin saturation < 30% or serum ferritin < 50 ng/ml. Infants with Hemoglobin Barts (Hb Barts) were excluded.

Results: A total of 109 infants were born during the study period and CBC with retic count performed after birth. 6 infants with Hb Barts positive newborn screen were excluded from the analysis. The demographic characteristics are depicted in Table 1. 32 infants had Ret-He ≤29 (31%) at birth. In the normal Ret-He group, the median hemoglobin was 15.8 g/dL, median Ret-He was 32.9 pg. In the low Ret-He group, median hemoglobin was 14.4 g/dL, median Ret-He was 26 pg, median serum iron was 69 mcg/dL, median ferritin was 236 ng/ml and median transferrin saturation was 25%. Iron studies were performed in 30 infants, and 26 infants (86.7%) with low Ret-He had at least one of the criteria for ID. Interestingly, 28 out of 29 infants had normal or elevated serum ferritin levels.

Conclusion: Low Ret-He was present in 31% of the VLBW infants at birth. 86.9% infants had evidence of low iron. Ret-He can be used to screen for ID in VLBW infants. Identifying ID at birth and appropriate treatment may prevent long term neurocognitive impairment in VLBW infants.