Optimizing Iron Supplementation by Monitoring Serum Ferritin Concentration

Implement a protocol for initiating and titrating Fe dosages based on therapeutic monitoring of ferritin levels and assess its impact on timing and dosing of Fe supplementation for preterm infants. Iron (Fe) is essential for growth, but optimal intake is controversial. Preterm infants often develop deficiency but are also susceptible to oxidant injury from overload. An AAP expert panel recommends Fe dosing based on serum ferritin levels. Our practice had been to supplement Fe (2 mg/kg/d) for all preterm infants receiving full-volume human milk feeds. Objectives were to implement a protocol for initiating and titrating Fe dosages based on therapeutic monitoring of ferritin levels and assess its impact on timing and dosing of Fe supplementation for preterm infants. Preterm infants (< 32 wks or < 1500 g, n=41) reaching full-volume feeds were included. Ferritin was measured every 2 wks. For ferritin 40-300 μg/L, Fe was started (2 mg/kg/d) or continued at current dose; for ferritin < 40 μg/L, Fe was increased by 1-2 mg/kg/d; for ferritin > 300 μg/L, Fe was held until ferritin decreased. Ferritin levels were not correlated with dietary Fe intake. Fe was initiated later, but peak doses were higher. It was deferred in 29% of infants because of ferritin > 300 μg/L, and only 42% of those were predictable from diet or transfusions. One infant required Fe despite transfusion. 34% of infants required escalating Fe doses. All formula-fed infants needed additional Fe despite intake of > 2 mg/kg/d from feeds. Fe requirements are not predictable based on dietary or transfusion history. Physiologic supplementation with Fe based on ferritin levels may decrease the incidence of deficiency and overload, improving outcomes for preterm infants.