Iron Supplementation Dosing for Infants
For healthy term infants, provide 1 mg/kg/day of elemental iron starting at 6 months if exclusively breastfed with inadequate iron from complementary foods; for preterm or low-birth-weight infants, provide 2-4 mg/kg/day (maximum 15 mg/day) starting at 1 month of age; and for treatment of iron-deficiency anemia in any infant, administer 3 mg/kg/day between meals. 1, 2
Preventive Supplementation by Infant Category
Healthy Term Infants (≥37 weeks, normal birth weight)
Exclusively breastfed: Start 1 mg/kg/day of iron drops at 6 months of age if the infant receives insufficient iron from complementary foods (less than 1 mg/kg/day from solid foods). 1
Formula-fed: Use iron-fortified formula containing 4-8 mg/L (providing approximately 0.6-1.2 mg/kg/day); no additional supplementation is needed. 3
Rationale: Term infants have sufficient iron stores from birth to approximately 6 months due to redistribution of iron from hemoglobin breakdown during physiologic anemia of infancy. 1, 4 After 6 months, iron requirements become critical at 0.9-1.3 mg/kg/day—the highest per-kilogram requirement of any life stage. 4
Preterm Infants (<37 weeks gestation)
Dose: 2-4 mg/kg/day of elemental iron (maximum 15 mg/day total). 1
Timing: Start at 1 month of age and continue until 12 months of age. 1
Special consideration: Preterm infants born <32 weeks should receive 2-3 mg/kg/day starting between 2-6 weeks of age. 1
Rationale: Preterm infants have lower iron endowment at birth due to interrupted third-trimester iron accretion and face additional depletion from phlebotomy losses and rapid catch-up growth. 5, 1
Low-Birth-Weight Infants
<2000 g: 2-4 mg/kg/day (maximum 15 mg/day), starting at 1 month of age. 1
2000-2500 g (marginally low birth weight): 1-2 mg/kg/day starting at 6 weeks of age. 1, 6, 3
Evidence: A randomized controlled trial demonstrated that 2 mg/kg/day in marginally low-birth-weight infants reduced iron-deficiency anemia prevalence from 9.9% (placebo) to 0% at 6 months, with no adverse effects on growth or morbidity. 6
Treatment of Iron-Deficiency Anemia
Therapeutic Dosing
Dose: 3 mg/kg/day of elemental iron (as ferrous sulfate drops). 1, 2, 7
Administration: Give between meals (on an empty stomach) to maximize absorption, as food reduces iron bioavailability by up to 50%. 2, 7
Duration: Continue for 4 weeks initially, then reassess hemoglobin. 1, 2
Confirming Response and Continuing Treatment
Response criteria: Hemoglobin should increase by ≥1 g/dL (or hematocrit by ≥3%) after 4 weeks to confirm iron-deficiency anemia. 1, 2, 7
If response confirmed: Continue iron therapy for an additional 2 months (total ~3 months) to replenish iron stores, then recheck hemoglobin. 1, 2, 7
If no response: Obtain further laboratory evaluation (MCV, RDW, serum ferritin) to identify alternative causes such as malabsorption, non-compliance, ongoing blood loss, or concurrent vitamin B12/folate deficiency. 2, 7
Formulation and Practical Dosing
Ferrous sulfate drops: Contain 25 mg elemental iron per mL. 7
Example: For a 10 kg child requiring 3 mg/kg/day (30 mg elemental iron), administer approximately 1.2 mL of ferrous sulfate drops daily. 7
Preferred formulation: Use ionic iron salts (ferrous sulfate, fumarate, or gluconate) rather than iron polysaccharide complex, as they are most cost-effective and provide known amounts of elemental iron. 2
Critical Implementation Points
Dietary Counseling
Introduce iron-fortified infant cereal at 4-6 months when the extrusion reflex disappears; two or more servings per day can meet iron requirements. 1
Introduce plain, pureed meats after 6 months when developmentally ready. 1
Provide vitamin C-rich foods (fruits, vegetables, juice) with meals after 6 months to enhance iron absorption. 1
Avoid: Do not feed unmodified cow's milk, goat's milk, or soy milk before 12 months of age. 1 Limit cow's milk to <24 oz/day in children aged 1-5 years. 1, 2
Common Pitfalls to Avoid
Do not give iron with meals or milk: Food and cow's milk reduce absorption by up to 50%. 2, 7
Do not co-administer with aluminum-based phosphate binders: These reduce iron absorption. 2
Do not rely on ascorbic acid supplementation: It does not improve ferrous iron absorption in clinical practice. 2
Do not discontinue for mild GI symptoms: Nausea, vomiting, and diarrhea are common but should not prompt discontinuation unless severe. 2
Avoid excessive dosing: Systemic iron toxicity with hepatocellular damage has been reported at 16 mg/kg. 2, 8
Monitoring for Long-Term Supplementation
Monitor hemoglobin and ferritin regularly in patients on long-term supplementation to prevent both iron deficiency and iron overload. 2, 7, 8
Recheck hemoglobin approximately 6 months after completing treatment to ensure sustained correction. 7
High-Risk Groups Requiring Screening
Screen for anemia at 9-12 months and 6 months later (15-18 months) in infants with the following risk factors: 1
- Preterm or low-birth-weight status
- Fed non-iron-fortified formula for >2 months
- Introduced to cow's milk before 12 months
- Breastfed without adequate iron from complementary foods after 6 months
- Consuming >24 oz daily of cow's milk
- Special health-care needs (medications interfering with iron absorption, chronic infection, inflammatory disorders, restricted diets, or extensive blood loss)
Note: The 2018 ESPGHAN/ESPEN guidelines 1 address parenteral iron in the context of parenteral nutrition and are not applicable to routine oral supplementation in healthy or anemic infants.