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

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] mu g/L; p = 0.85} or 60 d of life {147.2 [101.4-193.0] vs. 155.0 [106.6-203.6] mu g/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.