Iron Supplementation Dosing for Infants

Preventive Supplementation – Healthy Term Infants (≥37 weeks, normal birth weight)

The American Academy of Pediatrics recommends administering ferrous sulfate at 3 mg/kg per day of elemental iron, given between meals to maximize absorption, for infants with iron deficiency anemia 7, 8
Administration of ferrous sulfate should be timed between meals, as food can reduce iron bioavailability by up to 50% 8, 9
The treatment duration should be continued for 4 weeks initially, then reassess, and if response is adequate, continue for 2-3 additional months after correction to replenish iron stores 7, 8
Hemoglobin should increase by ≥1 g/dL (or hematocrit by ≥3%) after 4 weeks of treatment to confirm diagnosis 7, 8

The Centers for Disease Control and Prevention recommends 1 mg/kg/day of iron supplementation starting at 6 months for exclusively breastfed term infants if insufficient iron from complementary foods 10
Formula-fed term infants should use iron-fortified formula, with no additional supplementation needed 10
Preterm or low birthweight infants should receive 2-4 mg/kg/day (maximum 15 mg/day) of iron supplementation, starting at 1 month of age, and continuing until 12 months of age 10

Ionic iron salts (ferrous sulfate, fumarate, or gluconate) are the most cost-effective and provide known amounts of elemental iron, and should be used instead of iron polysaccharide complex 9
Ferrous sulfate should not be given with meals or milk, as food reduces absorption by up to 50%, and cow's milk should be limited to <24 oz/day in children 1-5 years 9, 10
Aluminum-based phosphate binders should not be co-administered with ferrous sulfate, as they reduce iron absorption 9
Ascorbic acid does not improve ferrous iron absorption, and should not be relied upon to enhance treatment efficacy 9
Mild GI symptoms such as nausea, vomiting, and diarrhea are common but should not prompt discontinuation of ferrous sulfate unless severe 8
If no response is seen after 4 weeks of treatment, further laboratory evaluation (MCV, RDW, serum ferritin) should be obtained to identify alternative causes 8
Systemic iron toxicity with hepatocellular damage has been reported at 16 mg/kg, and excessive dosing should be avoided 7, 8
Patients requiring repeated or prolonged courses of ferrous sulfate should be monitored for iron overload 7