What is the best treatment approach for a woman with iron-deficiency anemia, considering factors like menstrual bleeding and potential pregnancy?

Treatment of Iron-Deficiency Anemia in Women

For women with iron-deficiency anemia, prescribe oral ferrous sulfate 200 mg (65 mg elemental iron) once daily on an empty stomach, combined with vitamin C 500 mg to enhance absorption, and continue for 3 months after hemoglobin normalizes to replenish iron stores. 1

Dosing Strategy

Oral iron is first-line therapy for all women with iron-deficiency anemia unless specific contraindications exist. 1

• Prescribe ferrous sulfate 200 mg (65 mg elemental iron) once daily—never multiple times per day. 1, 2
• Once-daily dosing improves tolerance while maintaining equal or better iron absorption compared to multiple daily doses because hepcidin levels remain elevated for 48 hours after iron intake, blocking further absorption. 3, 4
• Add vitamin C (ascorbic acid) 500 mg with each iron dose to enhance absorption, especially critical in women with severely depleted iron stores. 1, 5, 6
• Take iron on an empty stomach for optimal absorption, though taking with food is acceptable if gastrointestinal side effects occur. 5, 6
• If daily dosing causes intolerable side effects, switch to alternate-day dosing (120 mg every other day), which increases fractional iron absorption and improves tolerance with similar efficacy. 3, 4

Alternative Oral Formulations

• If ferrous sulfate is not tolerated, try ferrous fumarate or ferrous gluconate—all oral iron formulations are equally effective, with choice based purely on cost and tolerability. 1, 6
• Ferrous sulfate remains the preferred formulation because it is consistently the least expensive option with no therapeutic advantage of any other oral iron preparation. 6, 2

Expected Response and Monitoring

• Check hemoglobin at 4 weeks, expecting a rise of approximately 2 g/dL. 1, 5, 6
• If hemoglobin fails to rise by 2 g/dL after 4 weeks despite confirmed adherence and absence of acute illness, further evaluate with MCV, RDW, and serum ferritin concentration. 1
• Continue oral iron for 3 months after hemoglobin normalizes to fully replenish iron stores—total treatment typically lasts 6-7 months. 1, 5, 6
• Monitor hemoglobin and red cell indices every 3 months for the first year after completing therapy, then again after another year. 1, 6

Special Considerations for Women of Childbearing Age

Non-Pregnant Women

• Screen all nonpregnant women for anemia every 5-10 years throughout childbearing years during routine health examinations. 1
• Annually screen women with risk factors for iron deficiency: extensive menstrual or other blood loss, low iron intake, or previous diagnosis of iron-deficiency anemia. 1
• Treat with oral iron 60-120 mg/day of elemental iron and counsel about correcting iron deficiency through diet. 1
• In women of African, Mediterranean, or Southeast Asian ancestry, mild anemia unresponsive to iron therapy may be due to thalassemia minor or sickle cell trait. 1

Pregnant Women

• Start oral low-dose (30 mg/day) iron supplements at the first prenatal visit for prevention. 1
• For confirmed anemia during pregnancy, prescribe 60-120 mg/day of elemental iron. 1
• Screen for anemia at the first prenatal care visit using pregnancy-specific anemia criteria. 1
• If hemoglobin is less than 9.0 g/dL or hematocrit is less than 27.0%, refer to a physician familiar with anemia during pregnancy for further medical evaluation. 1
• When hemoglobin or hematocrit becomes normal for the stage of gestation, decrease the dose of iron to 30 mg/day. 1
• Encourage pregnant women to eat iron-rich foods and foods that enhance iron absorption. 1

Postpartum Women

• Screen women at risk for anemia at 4-6 weeks postpartum using nonpregnant anemia criteria. 1
• Risk factors include anemia continued through the third trimester, excessive blood loss during delivery, and multiple birth. 1
• Treatment and follow-up for iron-deficiency anemia in postpartum women are the same as for nonpregnant women. 1
• If no risk factors for anemia are present, stop supplemental iron at delivery. 1

When to Switch to Intravenous Iron

Switch to IV iron if oral therapy fails or is contraindicated based on these specific criteria: 5, 6

• Intolerance to at least two different oral iron preparations (ferrous sulfate, ferrous fumarate, and ferrous gluconate). 5, 6
• Failure of ferritin levels to improve after 4 weeks of confirmed compliant oral therapy. 5, 6
• Active inflammatory bowel disease with hemoglobin <10 g/dL—inflammation-induced hepcidin elevation severely impairs oral iron absorption, making IV iron first-line therapy in this scenario. 6
• Post-bariatric surgery patients due to disrupted duodenal absorption mechanisms. 6
• Celiac disease with inadequate response to oral iron despite strict gluten-free diet adherence. 6
• Ongoing gastrointestinal blood loss exceeding oral replacement capacity. 6
• Need for rapid correction of anemia in symptomatic patients with circulatory compromise. 6

Preferred IV Iron Formulations

• Choose IV iron preparations that replace iron deficits in 1-2 infusions rather than multiple infusions to minimize risk and improve convenience. 6
• Ferric carboxymaltose (500-1000 mg single doses delivered within 15 minutes) is a preferred formulation. 6
• All IV iron formulations have similar overall safety profiles; true anaphylaxis is very rare (0.6-0.7%). 6
• Most reactions are complement activation-related pseudo-allergy (infusion reactions) that respond to slowing the infusion rate. 6

Identifying and Treating Underlying Causes

Always investigate the underlying cause of iron deficiency while treating with iron supplementation. 5, 6, 7, 8

In Premenopausal Women

• Assess menstrual blood loss first—menorrhagia, pregnancy, and breastfeeding account for iron deficiency in 5-10% of menstruating women. 6, 7, 8
• Consider pictorial blood loss assessment charts, which have 80% sensitivity and specificity for detecting menorrhagia. 6
• Screen for celiac disease with antiendomysial antibody and IgA measurement, as this is a common cause of malabsorption in younger patients. 6, 7
• Gastrointestinal endoscopy is not indicated in women under 45 years without upper GI symptoms, alarm features, or family history of colon cancer. 6

In Postmenopausal Women

• Evaluate for gastrointestinal blood loss and malabsorption—these are the most common causes in postmenopausal women and men. 7, 8
• Perform gastrointestinal endoscopy (upper endoscopy and colonoscopy) to identify sources of blood loss, especially colon cancer. 7, 8

Critical Pitfalls to Avoid

• Do not prescribe multiple daily doses of oral iron—this increases side effects without improving efficacy due to hepcidin-mediated absorption blockade. 5, 6, 3
• Do not stop iron therapy when hemoglobin normalizes—continue for 3 months to replenish stores. 1, 5, 6
• Do not overlook vitamin C supplementation when oral iron response is suboptimal—this significantly enhances absorption. 1, 5, 6
• Do not continue oral iron indefinitely without response—reassess after 4 weeks and switch to IV iron if hemoglobin fails to rise by 2 g/dL. 1, 5, 6
• Do not fail to identify and treat the underlying cause of iron deficiency while supplementing iron. 5, 6, 7, 8
• Do not assume adherence without verification—frequent side effects often lead to treatment discontinuation. 5
• Do not attribute iron deficiency anemia solely to aspirin or proton pump inhibitors without completing appropriate investigations. 5

Dietary Counseling

• Counsel patients about correcting iron deficiency through diet by eating iron-rich foods and foods that enhance iron absorption. 1
• Vegetarian women may require nearly double the supplementation due to lower absorption of non-heme iron. 5
• Avoid taking iron with tea, coffee, antacids, or proton pump inhibitors, as these significantly decrease absorption. 5