Iron Stores in Term and Late Preterm Small for Gestational Age and Appropriate for Gestational Age Neonates at Birth and in Early Infancy

Abstract

Objective: To compare body iron stores in late preterm and term small for gestational age (SGA) infants with gestation matched appropriate-for-gestational age (AGA) infants at birth and at 2 mo of age.

Methods: In this prospective observational study, live births of 34-42 wk gestation and SGA (<10th centile for GA) were enrolled along with gestation matched AGA (10th-90th centile for GA) infants. Infants' blood samples were taken within 2 h of delivery, and repeated at 60 ± 7 d of life. Primary outcome was serum ferritin at birth and 60 d of age. Secondary outcomes were hematocrit at birth and 60 d and need for transfusion until 60 d of life.

Results: A total of 37 SGA (gestation 37.2 ± 1.9 wk, birth weight 1861 ± 401 g) and 30 AGA infants (gestation 37.3 ± 1.9 wk, birth weight 2607 ± 405 g) were enrolled in the study. There was no difference in the serum ferritin between AGA and SGA infants at birth {median [IQR]: 254.0 [214.3-293.8] vs. 259.7 [217.8-301.5] μg/L; p = 0.85} or 60 d of life {147.2 [101.4-193.0] vs. 155.0 [106.6-203.6] μg/L; p = 0.81}. Mean hematocrit was 55.5 ± 9.6 vs. 52.4 ± 5.0 at birth (p = 0.10) and 32.1 ± 4.9 vs. 31.6 ± 3.8 at 60 d (p = 0.77) in SGA and AGA infants respectively. No infant required blood transfusion during the study period.

Conclusions: Iron stores of late preterm and term SGA infants are comparable to term AGA infants at birth and 2 mo of age. Recommendations on iron supplementation to these infants need to be formulated through appropriately designed randomized trials.

Keywords: Iron stores; Neonate; Small for gestational age.