Management of Iron Deficiency Anemia in a 25-Year-Old Woman
What the Labs Suggest
Your patient's modest hemoglobin rise from 10.7 to 11 g/dL after 2–3 weeks of oral iron confirms she is responding appropriately to treatment and validates the diagnosis of iron deficiency anemia. 1 The British Society of Gastroenterology guidelines state that an Hb rise of at least 10 g/L (1 g/dL) after 2 weeks of daily oral iron is strongly predictive of sustained haematological response (sensitivity 90.1%, specificity 79.3%). 1 Her initial labs—ferritin 5.83 µg/L, transferrin saturation 9%, microcytosis (MCV 77.5), elevated RDW (18.3)—are pathognomonic for iron deficiency anemia. 2, 3
Duration of Iron Supplementation
Continue oral iron for 2–3 months after hemoglobin normalizes to fully replenish iron stores. 1
- The British Society of Gastroenterology recommends 50–100 mg elemental iron daily (e.g., one ferrous sulfate 200 mg tablet) taken on an empty stomach. 1
- Total treatment duration typically extends 5–6 months: time to normalize hemoglobin plus an additional 2–3 months for store repletion. 3, 4
- The AGA guidelines note that once-daily dosing is optimal because hepcidin elevation after each dose blocks further absorption for up to 48 hours, making multiple daily doses ineffective and more likely to cause side effects. 1
When to Recheck Labs
Recheck hemoglobin every 4 weeks until it normalizes (≥12 g/dL for women). 1
- Once hemoglobin is normal, continue iron for 2–3 months, then recheck CBC and iron studies (ferritin, transferrin saturation) to confirm store repletion. 1
- Target ferritin should be ≥50 ng/mL in the absence of inflammation. 1
- Do not check iron parameters within 4 weeks of starting treatment, as circulating iron interferes with assays and produces spurious results. 1
Evaluation for Occult Blood Loss
Yes, you must evaluate for a bleeding source in a 25-year-old woman with confirmed iron deficiency anemia. 2, 3, 4
Specific Questions to Ask:
- Menstrual history: Heavy menstrual bleeding (soaking through pads/tampons hourly, clots >1 inch, periods >7 days) is the most common cause in premenopausal women. 4, 5
- Gastrointestinal symptoms: Melena, hematochezia, chronic diarrhea, abdominal pain, or change in bowel habits. 6
- Dietary history: Vegetarian/vegan diet, pica (ice chewing, clay, starch), or recent bariatric surgery. 1, 5
- Medication use: NSAIDs, aspirin, anticoagulants that increase GI bleeding risk. 6
- Family history: Colon cancer, inflammatory bowel disease, celiac disease, or hereditary hemorrhagic telangiectasia. 5
When to Pursue GI Evaluation:
- If menstrual bleeding does not fully explain the severity of anemia (ferritin <6 µg/L is profound depletion), consider upper endoscopy with duodenal biopsies to exclude celiac disease (found in 2–3% of IDA cases) and colonoscopy to exclude colonic sources. 2, 3
- In premenopausal women with clear heavy menstrual bleeding and appropriate response to iron, GI evaluation can be deferred unless red-flag symptoms are present (weight loss, GI symptoms, family history of GI malignancy). 4, 6
- All adult men and postmenopausal women with IDA require complete GI evaluation regardless of symptoms. 2, 3
Patient Counseling
Explain that her restless leg syndrome symptoms should improve as iron stores replenish, since iron deficiency is a recognized cause of RLS even without anemia. 5
Key Counseling Points:
- Adherence: Take iron on an empty stomach (1 hour before or 2 hours after meals) for best absorption; if GI side effects occur, taking with food is acceptable but reduces absorption. 1
- Side effects: Constipation (12%), diarrhea (8%), nausea (11%), and dark stools are common but not dangerous. 1
- Duration: Emphasize that treatment continues for months after she feels better to prevent recurrence. 1
- Avoid: Do not take iron with calcium supplements, antacids, or proton pump inhibitors, which impair absorption. 1, 5
- Enhance absorption: Taking with vitamin C (orange juice) or meat protein improves uptake. 1
Common Pitfalls to Avoid
- Do not stop iron when hemoglobin normalizes—this only corrects anemia, not the depleted stores that caused it. 1, 3
- Do not check ferritin too early—wait at least 4 weeks after starting treatment to avoid falsely elevated results from circulating iron. 1
- Do not assume compliance—if hemoglobin fails to rise ≥10 g/L after 2 weeks, consider non-adherence, ongoing blood loss, malabsorption, or need for IV iron. 1
- Do not overlook celiac disease—it is a common occult cause of IDA in young women and requires duodenal biopsy for diagnosis. 2, 3