What is the treatment for a woman with low ferritin (iron deficiency)?

Treatment of Low Ferritin in Women

All women with low ferritin should receive oral iron supplementation with ferrous sulfate 200 mg three times daily (or equivalent formulations) to correct deficiency and replenish body stores, continuing for three months after correction to fully restore iron stores. 1

Initial Treatment Approach

First-Line Oral Iron Therapy

• Ferrous sulfate 200 mg three times daily is the most cost-effective first-line treatment 1
• Each 324 mg tablet of ferrous sulfate contains 65 mg elemental iron 2
• Alternative formulations (ferrous gluconate, ferrous fumarate) are equally effective if ferrous sulfate is not tolerated 1
• Liquid preparations may be better tolerated when tablets cause side effects 1

Recent evidence suggests alternate-day dosing may optimize absorption: giving 60-120 mg elemental iron on alternate days in the morning maximizes fractional absorption and reduces gastrointestinal side effects, as daily dosing increases hepcidin for 24 hours and blocks subsequent iron absorption 3

Enhancing Absorption

• Add ascorbic acid (vitamin C) when response to oral iron is poor, as it significantly enhances iron absorption 1
• Take iron in the morning rather than afternoon or evening to avoid circadian hepcidin increases 3

Age-Specific Investigation Requirements

Women Under 45 Years

• Pre-menopausal women with ferritin <15 ng/mL commonly have iron deficiency (5-10% prevalence) due to menstrual loss, pregnancy, or breastfeeding 1
• Investigation is only required if upper GI symptoms are present (then perform endoscopy with small bowel biopsy) 1
• Without GI symptoms: test for celiac disease with antiendomysial antibodies and IgA levels (to exclude IgA deficiency that makes testing unreliable) 1
• Colonic investigation only if specific indications exist 1

Women 45 Years and Older

• All women ≥45 years require bidirectional endoscopy (upper endoscopy with small bowel biopsy AND colonoscopy or barium enema) due to increasing incidence of gastrointestinal pathology with age 1
• Non-invasive testing for H. pylori and celiac disease should be performed first 1

Monitoring and Follow-Up

Expected Response

• Hemoglobin should rise by 2 g/dL after 3-4 weeks of oral iron therapy 1
• Failure to respond indicates poor compliance, misdiagnosis, continued blood loss, or malabsorption 1

Duration of Treatment

• Continue iron supplementation for 3 months after anemia correction to fully replenish iron stores 1
• Target ferritin >100 ng/mL to confirm adequate iron store restoration 1

Long-Term Monitoring Schedule

• Check hemoglobin and red cell indices every 3 months for one year, then again after another year 1
• Repeat ferritin testing if hemoglobin or MCV falls below normal 1
• Resume oral iron if deficiency recurs 1

When to Use Intravenous Iron

Parenteral iron should only be used when:

• Intolerance to at least two different oral iron preparations 1
• Documented non-compliance with oral therapy 1
• Inflammatory bowel disease with active inflammation compromising absorption 1
• Ongoing blood loss unresponsive to oral iron 1

Important caveat: Intravenous iron is painful (intramuscular), expensive, carries anaphylaxis risk, and provides no faster hemoglobin rise than oral preparations 1

Diagnostic Thresholds

• Ferritin <15 ng/mL confirms iron deficiency in women without inflammatory conditions 1
• Ferritin <45 ng/mL is the recommended threshold when anemia is present 1, 4
• In inflammatory conditions, ferritin may be elevated despite iron deficiency; consider transferrin saturation <20% for diagnosis 4
• Some evidence suggests physiologic ferritin cutoff should be 50 ng/mL, as 30-50% of healthy women have no marrow iron stores at lower levels 5

Common Pitfalls to Avoid

• Do not stop iron supplementation when hemoglobin normalizes—continue for 3 additional months to replenish stores 1
• Do not perform faecal occult blood testing—it is insensitive and non-specific 1
• Do not give divided doses throughout the day—morning single doses on alternate days optimize absorption 3
• Do not use parenteral iron as first-line therapy unless specific contraindications to oral iron exist 1