Management of Iron Deficiency Anemia in a 35-Year-Old Premenopausal Woman
Continue oral iron supplementation for at least 3 months after hemoglobin normalization to replenish iron stores, monitor hemoglobin and ferritin every 3-4 weeks to assess response, and evaluate for menorrhagia as the likely cause given her regular cycles. 1
Immediate Management Steps
Continue and Optimize Oral Iron Therapy
Maintain ferrous sulfate 200 mg three times daily (or equivalent ferrous gluconate/fumarate) as this remains first-line therapy for premenopausal women with iron deficiency anemia 1
Duration of treatment is critical: Iron supplementation should continue for 3 months after correction of anemia to adequately replenish body stores 1
If tolerability is an issue, consider taking iron on alternate days or with meals, though absorption is optimal on an empty stomach 1
Add ascorbic acid (vitamin C) 500 mg with iron doses to enhance absorption, particularly important given the low ferritin of 7 ng/mL 1
Monitor Response to Therapy
Check hemoglobin in 3-4 weeks: Expect a rise of approximately 2 g/dL after 3-4 weeks of treatment 1
Failure to respond suggests poor compliance (most common), continued blood loss, malabsorption, or misdiagnosis 1
Once hemoglobin normalizes, monitor hemoglobin and MCV every 3 months for one year, then again after another year 1
Check ferritin when hemoglobin normalizes to confirm adequate store repletion 1
Evaluation for Underlying Cause
Assess Menstrual Blood Loss
Menorrhagia is the most likely cause in a 35-year-old woman with regular cycles, as iron deficiency occurs in 5-10% of menstruating women 1
Menstrual loss, pregnancy, and breastfeeding are the usual causes in premenopausal women 1
Consider pictorial blood loss assessment charts (sensitivity and specificity ~80% for detecting menorrhagia) 1
Gynecologic evaluation may be warranted if menorrhagia is confirmed
Limited GI Investigation Needed at This Age
Women under 45 years with regular menstrual cycles typically do not require extensive GI evaluation unless there are specific GI symptoms, occult blood in stool, or failure to respond to iron therapy 1
The British Society of Gastroenterology guidelines specifically note that the increasing incidence of important GI pathology with age makes investigation more important for those over 45 years 1
Evaluate for dietary deficiency and NSAID use 1
Consider testing for Helicobacter pylori infection as a potential cause 1
When to Consider Intravenous Iron
Switch to IV iron if:
Intolerance to at least two oral iron preparations 1
Non-compliance with oral therapy 1
Continued blood loss despite oral supplementation 1
Malabsorption conditions are identified (celiac disease, post-bariatric surgery) 1, 2
No response after 3-4 weeks of adequate oral therapy 1
Note: Parenteral iron is more expensive, can cause anaphylactic reactions, and provides no faster hemoglobin rise than oral preparations when absorption is intact 1
Common Pitfalls to Avoid
Stopping iron too early: The most common error is discontinuing iron once hemoglobin normalizes without the additional 3 months needed to replenish stores 1, 3
Not addressing compliance: Poor adherence is the most common cause of treatment failure 1, 3
Over-investigation in young women: Extensive GI workup is generally not indicated in premenopausal women with regular cycles unless specific red flags are present 1
Assuming dietary deficiency alone: While dietary assessment is important, ongoing blood loss (menstrual) is the more likely primary cause in this demographic 1
Expected Outcomes
Most patients in whom a cause is not found after appropriate evaluation (when indicated) do not have recurrent iron deficiency if adequately treated 1
Quality of life improves with correction of anemia and iron deficiency, including resolution of fatigue, exercise intolerance, and restless legs syndrome 1, 2
Further investigation is only necessary if hemoglobin and MCV cannot be maintained with periodic iron supplementation 1