Iron status at birth and at 4 weeks in preterm-SGA infants in comparison with preterm and term-AGA infants

Objective: To determine the iron status at birth in preterm small for gestational age (SGA) in comparison with preterm appropriate for gestation (AGA) and term-AGA infants. Methods: Mother-infant pairs with gestation of <37 weeks, both SGA, and preterm-AGA and term-AGA as control were enrolled. Maternal, cord blood and infant blood samples at 4 weeks were obtained for various iron indices - cord serum ferritin, proportion of infants with "low" serum ferritin, serum ferritin at 4 weeks and correlation among maternal and neonatal iron indices - hemoglobin, serum ferritin and total iron-binding capacity. Results: There were 50 mother-infant pairs in each group. Cord serum ferritin levels were less in preterm-SGA group as compared to preterm-AGA group (median [interquartile range]: 68 [30 113] vs. 120 [73 127], p = 0.002) and preterm-AGA had less cord ferritin than term-AGA (141 [63 259], p = 0.006). The proportion of the infants with "low" serum ferritin was more in preterm-SGA than in preterm-AGA (16 [32%] vs. 5 [10%], p = 0.01). The serum ferritin levels at follow-up were also less in preterm-SGA as compared to preterm-AGA (143.5 +/- 101 vs. 235.1 +/- 160, p = 0.004). Other cord blood iron indices and follow-up serum ferritin levels were similar. There was no correlation among various maternal and neonatal cord iron parameters. Conclusions: Preterm-SGA infants have lesser total iron stores as compared to gestation-matched AGA infants, which is again lesser than term infants. Future studies can be planned to look at iron status at 12 months as well as their neurodevelopmental outcome.