Neonatal Drug Therapy Manual

Ferrous Sulfate

Disclaimer: Official controlled document is the CHEO and Ottawa Hospital online copy. It is the responsibility of user to ensure that any paper copy version is the same as the online version before use.

Alternate Name(s): 
Original Date: 
June 1996
Revised Date: 
Nov 2023
  • Prophylaxis and treatment of iron deficiency anemia
  • PO;  with feeds

Doses are expressed in elemental iron


Goal is to initiate iron supplementation between DOL 15 and 21 in all LBW (<2.5 kg) infants who have reached full enteral feeds.

  • A supplement of 3 mg/kg/day to be started in all infants with BW < 2 kg who are receiving > 50% EBM/PHDM  
  • A supplement of 2 mg/kg/day to be started in all infants with BW 2-2.5 kg who are receiving > 50% EBM/PHDM  
  • No supplement will be started in infants receiving iron-fortified formula; infants with a BW <2 kg will be started on premature infant formula to ensure adequate iron intake.



  • preterm/term: 4 - 6 mg/kg/day


Discontinuation of Fe supplementation (see chart below for additional info on monitoring and adjusting dose):

  • Infants with a birth weight of 2.0 kg to 2.5 kg, should receive an iron supplement of 1-2 mg/kg/day for the first 6 months of age.
  • Infants with a birth weight less than 2.0 kg, should receive an iron supplement of 2-3 mg/kg/day for the first year of age.
Side Effects: 
  • GI: mild gastrointestinal upset, constipation (rare), dark stools
Parameters to Monitor: 
  • CBC, Reticulocyte count
  • Ferritin: goal is a level between 101 and 224 ug/L. See table below for dose adjustment and monitoring.
Initial Ferritin Testing

Around 4 weeks of age or after at least 2 weeks of iron supplementation (try to batch with other blood work as applicable).  

Consider delaying if the patient is septic, unstable or recently transfused*.  

Serum Ferritin level ≤ 35ug/L   36-100ug/L   101-224ug/L   225-299ug/L   ≥300ug/L
Iron supplementation   Increase Fe by 2mg/kg/day to maximum of 5mg/kg/day total**.   Increase Fe by 1mg/kg/day Continue with same dose   Decrease Fe by 1mg/kg/day D/C Fe supplementation  
Blood work frequency Every 2 weeks   Every 3 weeks   Every 3 weeks   Every 3 weeks   2 weeks after D/C. If <300, resume Fe supp. But at a lower dose than previous.  

Goal at discharge or term corrected (whichever comes first): Continue with the same supplementation if ferritin is between 100-224 and can stop routine testing of ferritin levels.  Long term follow up per CPS guidelines. 

*Serum ferritin level should not be done within one week of PRBC transfusion  
**Dosage should not exceed 5-6mg/kg/day for longer than 2 weeks from enteral and supplemental sources combined  

  1. 75 mg of ferrous sulfate = 15 mg elemental iron = 1 mL Fer-In-Sol drops
  2. Iron content of common feeds for premature infants:
  • EBM (Expressed Breast Milk) with Abbott® HMF (TOH Human Milk Fortifier) supplies negligible iron.
  • EBM with Enfamil® HMF (CHEO human milk fortifier) supplies approximately 2 mg/kg/day of iron
  • Formulas at 20 kcal/oz supply approximately 2mg/kg/day of iron
  • (1) Siddappa AM, Rao R, Long JD, Widness JA, Georgieff MK. The assessment of newborn iron stores at birth; a review of the literature and standards for ferritin concentration. Neonatology 2007;92(2):73-82 doi:10.1159/000100805

    (2) Rao R, Georgieff MK. Iron and fetal and neonatal nutrition. Semin Fetal Neonatal Med 2007;12(1):54-63

    (3) Unger SL, Fenton TR, Jetty R, Critch JN, O’Connor DL. Iron requirements in the first two years of life. Paediatr Child Health 2019 Dec;24(8):555-56.doi:10.1093/pch/pxz148.Epub 2019 Dec 9.

    (4) Jin HX, Wang RS, Chen SJ, Wang AP, Liu XY. Early and late iron supplementation for low birth weight infants: A meta-analysis. Ital J Pediatr 2015;41(1):16

    (5) German KR, Juul SE. Iron and Neurodevelopment in Preterm Infants: A Narrative Review. Nutrients. 2021;13(11):3737. Published 2021 Oct 23. doi:10.3390/nu13113737

    (6) Wu Y, Song J, Wang Y, Wang X, Culmsee C, Shu C. The potential role of ferroptosis in neonatal brain injury. Front Mol Neurosci 2019;13:115, doi:10.3389/fnins.2019.00115

    (7) Berger HM, Mumby S, Gutteridge JM. Ferrous ions detected in iron-overloaded cord blood plasma from preterm and term babies: implications

    (8) Wessling-Resnick M. Excess iron: considerations related to development and early growth. Am J Clin Nutr. 2017;106(Suppl 6):1600S-1605S. doi:10.3945/ajcn.117.155879

    (9) Ho, T., et al. (2021). "Intestinal Microbiome in Preterm Infants Influenced by Enteral Iron Dosing." Journal of pediatric gastroenterology and nutrition 72(5): e132-e138.

    (10) Baker RD, Greer FR, Committee on Nutrition American Academy of Pediatrics. Diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants and young children (0-3). 2010; Pediatrics;126(5):1040-1050.)

    (11) Agostoni C, Buonocore G, Carnielli VP, DeCurtis M, Darmaun D, Decsi T, Domellof M, Embleton ND, Fusch C, Genzel-Boroviczeny O, Goulet O, Kalhan SC, Kolacek S, Koletzko B, Lapillonne A, Mihatsch W, Moreno L, Neu J, Poindexter B, Puntis J, Putet G, Rigo J, Riskin A, Salle B, Sauer P, Shamir R, Szajewska H, Thureen P, Turck D, vanGoudoever JB, Ziegler EE and Nutrition Committee on Nutrition. Enteral nutrient supply for preterm infants: commentary from the European Society of Paediatric Gastroenterology, Hepatology and Nutrition Committee on Nutrition. 2010 JPGN;50(1):85-91

    (12) Domellof M. Nutritional care of premature infants: microminerals. World Rev Nutr Diet 2014;110:121-13

    (13) Mills RJ, Davies MW. Enteral iron supplementation in preterm and low birth weight infants. Cochrane Database of Systematic Reviews 2012, Issue 3. Art. No.: CD005095. DOI: 10.1002/14651858.CD005095.pub2

    (14) Franz AR, Mihatsch WA, Sander S, Kron M, Pohlandt F. Prospective randomized trial of early versus late enteral iron supplementation in infants with a birth weight of less than 1301 grams. Pediatrics 2000, 106;700-706 doi:10.1542/peds.106.4.700.

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