How should I evaluate and treat a 45‑55‑year‑old perimenopausal woman with heavy menstrual bleeding (menorrhagia) resulting in iron‑deficiency microcytic anemia?

Management of Microcytic Anemia in Perimenopausal Menorrhagia

Start oral ferrous sulfate 200 mg once daily immediately, continue for 3 months after hemoglobin normalizes, and simultaneously address the underlying menorrhagia to prevent recurrence. 1

Immediate Iron Replacement Strategy

• Initiate ferrous sulfate 200 mg once daily as first-line therapy – this is the most cost-effective treatment for iron deficiency anemia secondary to menorrhagia 1

• Once-daily dosing is superior to multiple daily doses because it improves gastrointestinal tolerance while maintaining equal or better iron absorption due to hepcidin regulation 1

  • Avoid prescribing multiple daily doses, as this increases gastrointestinal side effects without improving efficacy due to hepcidin-mediated absorption blockade 1

• Add vitamin C (ascorbic acid) 500 mg with each iron dose to enhance absorption, particularly when iron stores are severely depleted 1

• If ferrous sulfate is not tolerated, switch to ferrous gluconate or ferrous fumarate, which are equally effective alternatives 1, 2

• Continue iron therapy for 3 months after hemoglobin normalizes to fully replenish body iron stores – premature discontinuation leads to recurrence 1, 2

Expected Response and Monitoring Protocol

• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment 1

• Monitor hemoglobin and red cell indices at 3-month intervals for the first year, then again after another year 1, 2

• If hemoglobin or MCV falls below normal during follow-up, restart iron supplementation and check ferritin in doubtful cases 1, 2

When to Switch to Intravenous Iron

• Consider IV iron only if the patient cannot tolerate at least two different oral iron preparations, or if oral iron fails to improve ferritin levels after 4 weeks of compliant therapy 1, 2

• Ferric carboxymaltose (Injectafer) is FDA-approved for iron deficiency anemia in patients intolerant to oral iron or with unsatisfactory response to oral iron 3

  • In clinical trials of women with heavy uterine bleeding (47% of study population), IV ferric carboxymaltose increased hemoglobin by 1.6 g/dL (from 10.6 to 12.2 g/dL) by Day 35 3

• All IV iron formulations have similar safety profiles, with true anaphylaxis being rare (0.6-0.7%) 1

• IV ferric carboxymaltose has been shown to be a safer alternative to blood transfusion in severe anemia from menorrhagia, even with hemoglobin levels as low as 4-8 g/dL 4

Addressing the Underlying Menorrhagia

• While treating anemia, simultaneously address the underlying menorrhagia to prevent recurrence 1

• The most effective medical therapy for perimenopausal menorrhagia is intrauterine levonorgestrel 5

• Other options include oral progestogens, combined oral contraceptive pill, tranexamic acid, mefenamic acid, danazol, and GnRH analogues 5

Age-Specific Gastrointestinal Evaluation

This is a critical decision point based on age:

• For women under 45 years with menorrhagia-related anemia: Focus on treating menorrhagia and iron deficiency; gastrointestinal investigation is only needed if upper GI symptoms are present 1

• For women over 45 years (including perimenopausal women aged 45-55) with iron deficiency anemia: Perform a full gastrointestinal evaluation (upper endoscopy with small bowel biopsy and colonoscopy), even if menorrhagia is present, due to the increasing incidence of gastrointestinal malignancy with age 1

  • The British Society of Gastroenterology guidelines emphasize that asymptomatic colonic and gastric carcinoma may present with iron deficiency anemia in this age group, and exclusion of these conditions is of prime concern 6

Failure to Respond Algorithm

• If hemoglobin fails to rise by 2 g/dL after 4 weeks despite compliant oral iron therapy: Verify patient adherence, assess for continued menstrual blood loss, and evaluate for malabsorption 1

• If anemia does not resolve within 6 months despite appropriate iron therapy and menorrhagia control: Reassess for ongoing occult blood loss from gastrointestinal sources, and perform upper endoscopy and colonoscopy 1

Critical Pitfalls to Avoid

• Do not stop iron therapy when hemoglobin normalizes – continue for 3 months to replenish stores 1, 2

• Do not use parenteral iron as first-line unless there is documented intolerance to at least two oral preparations 1, 2

• Do not overlook vitamin C supplementation when oral iron response is suboptimal 1

• Do not skip gastrointestinal evaluation in women over 45 years, even when menorrhagia is the obvious cause, as this age group requires exclusion of GI malignancy 6, 1