What is the recommended treatment for a woman with iron‑deficiency anemia (iron saturation 4 %, serum iron 18 µg/dL, ferritin 9 ng/mL, hemoglobin 9.6 g/dL, mean corpuscular volume 70 fL)?

Management of Severe Iron Deficiency Anemia in a Premenopausal Woman

This patient has severe absolute iron deficiency anemia requiring immediate oral iron supplementation and concurrent investigation for gastrointestinal blood loss, with celiac disease and Helicobacter pylori screening mandatory before considering endoscopy.

Confirming the Diagnosis

The laboratory pattern definitively confirms severe iron deficiency anemia:

• Ferritin 9 ng/mL is far below the diagnostic threshold of <15 μg/L, which has 99% specificity for absolute iron deficiency 1, 2
• Iron saturation 4% is critically low (normal threshold >16-20%), indicating severely impaired iron delivery to bone marrow for red blood cell production 1, 2
• Serum iron 18 µg/dL with MCV 70 fL confirms microcytic, hypochromic anemia from iron-restricted erythropoiesis 1
• Hemoglobin 9.6 g/dL meets WHO criteria for moderate anemia in women (Hb <12 g/dL) 1

Immediate Treatment Protocol

Start oral iron supplementation immediately—do not wait for diagnostic workup completion 2:

• Ferrous sulfate 65 mg elemental iron daily (or 60-65 mg every other day if gastrointestinal side effects occur) 2
• Alternate-day dosing improves absorption by 30-50% and reduces nausea, constipation, and diarrhea 2
• Take on empty stomach for optimal absorption; switch to with-meals dosing only if intolerable 2
• Expected response: hemoglobin should rise ≥10 g/L (1 g/dL) within 2 weeks 2, 3

Mandatory Concurrent Investigation

Screen All Patients First

Before proceeding to endoscopy, obtain:

1. Celiac disease screening with tissue transglutaminase IgA antibodies—celiac disease accounts for 3-5% of iron deficiency cases and causes treatment failure if missed 1, 2

2. Non-invasive Helicobacter pylori testing (stool antigen or urea breath test)—the organism impairs iron absorption 1, 2

3. Detailed menstrual history—heavy menstrual bleeding is the most common cause of iron deficiency in premenopausal women 2, 4

Indications for Bidirectional Endoscopy

Reserve upper and lower GI endoscopy for premenopausal women only when 2:

• Age ≥50 years (higher malignancy risk)
• Gastrointestinal symptoms present (abdominal pain, altered bowel habits, visible blood in stool)
• Positive celiac or H. pylori testing requiring confirmation
• Failure to respond to adequate oral iron after 8-10 weeks (no Hb rise ≥10 g/L)
• Strong family history of colorectal cancer

In young, asymptomatic premenopausal women with heavy menses and negative celiac/H. pylori screening, empiric oral iron supplementation without immediate endoscopy is appropriate 2.

When to Switch to Intravenous Iron

Transition to intravenous ferric carboxymaltose (15 mg/kg, maximum 1000 mg per dose) if any of the following apply 2:

• Severe oral iron intolerance (marked nausea, constipation, diarrhea)
• Confirmed malabsorption (celiac disease, inflammatory bowel disease, post-bariatric surgery)
• Ongoing blood loss exceeding oral replacement capacity
• Lack of hemoglobin response after 8-10 weeks of adequate oral iron
• Chronic inflammatory conditions (chronic kidney disease, heart failure, cancer)

IV iron produces reticulocytosis within 3-5 days and yields mean hemoglobin increase of ≈8 g/L over 8 days, demonstrating superior efficacy in these populations 2.

Follow-Up and Monitoring

• Repeat CBC and ferritin at 8-10 weeks to assess therapeutic response 2, 3
• Target ferritin >100 ng/mL to fully restore iron stores and prevent recurrence 2
• Continue oral iron for 3 months after hemoglobin normalizes—stopping prematurely leaves ferritin depleted and causes rapid relapse 2
• For menstruating females, screen ferritin every 6-12 months to detect early depletion before anemia develops 2

Critical Pitfalls to Avoid

• Do not assume heavy menses alone explains the severity—with ferritin 9 ng/mL and Hb 9.6 g/dL, gastrointestinal pathology must be excluded if celiac/H. pylori screening is positive or if oral iron fails 1, 2
• Do not overlook celiac disease screening—its 3-5% prevalence in iron deficiency makes it a common cause of treatment failure 1, 2
• Do not discontinue iron once hemoglobin normalizes—an additional 3 months is required to achieve ferritin >100 ng/mL 2
• Do not delay endoscopy in patients ≥50 years or with alarm symptoms—gastrointestinal malignancy can present solely with iron deficiency 1, 2