What is the likely diagnosis and treatment for a 25-year-old woman with fatigue, shortness of breath, occasional palpitations, and heavy menstrual periods?

Likely Diagnosis: Iron Deficiency Anemia Secondary to Heavy Menstrual Bleeding

This 25-year-old woman most likely has iron deficiency anemia (IDA) caused by heavy menstrual bleeding, and she should be started immediately on oral iron supplementation with ferrous sulfate 324 mg (65 mg elemental iron) daily while simultaneously addressing the underlying menstrual blood loss. 1, 2, 3

Clinical Presentation Analysis

The constellation of symptoms—fatigue, shortness of breath, occasional palpitations, and heavy menstrual periods—is classic for IDA in a reproductive-aged woman:

• Fatigue and shortness of breath occur because anemia reduces the blood's oxygen-carrying capacity, leading to decreased tissue oxygen delivery that becomes progressively more pronounced with daily activities 2
• Palpitations represent a compensatory cardiovascular response to maintain tissue oxygenation despite reduced hemoglobin 4
• Heavy menstrual bleeding is responsible for recurrent blood loss, which accounts for 94% of iron deficiency anemia cases in this demographic 3, 5

The symptoms are disproportionate to exertion level but improve with rest, distinguishing this from primary cardiac pathology 4. Heavy menstrual bleeding affects over 20% of reproductive-aged women and is the major contributor to iron deficiency in this population 5, 6.

Diagnostic Approach

Initial Laboratory Testing

Obtain a complete blood count with indices and iron studies immediately 1, 2, 3:

• Hemoglobin <120 g/L confirms anemia in women 7
• Ferritin <45 ng/mL is diagnostic of iron deficiency in patients without inflammation 3
• Ferritin 46-99 ng/mL plus transferrin saturation <20% also confirms iron deficiency 3
• Mean corpuscular volume (MCV) will typically be low in established IDA 1

Additional Considerations

In younger women with a plausible cause (heavy menstrual bleeding), extensive gastrointestinal investigation is not immediately necessary 3. However, noninvasive testing for Helicobacter pylori and celiac disease should be performed as both are common causes of iron deficiency anemia 1, 3.

Treatment Strategy

Oral Iron Replacement (First-Line)

Initiate ferrous sulfate 324 mg (65 mg elemental iron) once daily 8, 3:

• Each tablet provides 362% of the recommended daily intake 8
• Every-other-day dosing improves absorption and may reduce gastrointestinal side effects 3
• Lower doses should be used if side effects occur 2
• Add ascorbic acid (vitamin C) if response is poor to enhance iron absorption 2

Monitoring Response

Evaluate treatment response in 2-4 weeks 3:

• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of proper iron therapy 2
• Reticulocyte count should increase within 7-10 days
• Serum ferritin may take up to 5 years to normalize in severe cases 7

Alternative Treatment

Consider intravenous iron if 3:

• Patient cannot tolerate oral iron (approximately 50% have decreased adherence due to adverse effects) 3
• Inadequate response to oral therapy after 4 weeks
• Ongoing iron losses exceed absorptive capacity 5
• Rapid iron repletion is required 5

Hypersensitivity to newer intravenous iron formulations is rare (<1%) 3.

Simultaneous Management of Heavy Menstrual Bleeding

Treating iron deficiency alone is insufficient—the underlying menstrual blood loss must be addressed concurrently 5, 6:

• Options include hormonal contraceptives, levonorgestrel intrauterine system, or tranexamic acid
• Gynecologic evaluation should be pursued to determine the cause of heavy menstrual bleeding
• Only 8% of anemic women with heavy menstrual bleeding receive appropriate iron supplementation, representing a significant treatment gap 7

Impact on Quality of Life

The interrelationship between heavy menstrual bleeding and iron deficiency is poorly appreciated and frequently normalized 6:

• Iron deficiency adversely impacts quality of life on a daily basis, affecting cognitive function, work performance, and school attendance 6
• Correction of anemia significantly improves health-related quality of life, with improvements in energy, physical functioning, social functioning, and reductions in anxiety and depression scores within 12 months 7
• The insidious nature of these conditions often leads to normalization by patients, healthcare providers, and society 6

Critical Pitfalls to Avoid

• Do not assume primary care is managing the anemia—as the treating clinician, take the lead in diagnosing and initiating treatment 5
• Do not normalize the symptoms—fatigue and heavy periods are common but not normal and require investigation 6
• Do not delay iron supplementation—even mild iron deficiency without anemia impairs quality of life and cognitive function 2, 6
• Do not treat anemia without addressing the bleeding source—dual management is essential for long-term success 5