Can menstrual periods cause iron deficiency anemia?

Menstrual Periods and Iron Deficiency Anemia

Yes, menstrual periods can definitely cause iron deficiency anemia, particularly when menstrual blood loss is heavy (≥80 mL/month), which affects approximately 10% of women of childbearing age. 1

Mechanism and Risk

Menstruation represents a significant source of iron loss for women throughout their reproductive years. Here's how menstrual periods contribute to iron deficiency anemia:

• Regular iron loss: The average woman loses approximately 0.55-0.87 mg of iron per day through menstruation 2, 3
• Heavy menstrual bleeding (HMB): Women with menorrhagia (heavy periods) lose 5-6 times more iron per cycle (average 5.2 mg vs 0.87 mg in normal menses) 2
• Cumulative effect: When menstrual iron losses exceed dietary iron intake over time, iron stores become depleted, leading first to iron deficiency and eventually to iron deficiency anemia

Prevalence and Risk Factors

Iron deficiency is extremely common in women of reproductive age:

• 11% of nonpregnant women aged 16-49 years have iron deficiency 1
• 3-5% have iron deficiency anemia 1
• 15-35% of female athletes have iron deficiency, with some studies suggesting rates >50% 1
• 68.2% of premenopausal African-American women in one study had iron deficiency, with 18.2% having anemia 4

Risk factors that increase the likelihood of developing iron deficiency anemia from menstruation include:

• Heavy menstrual bleeding (>80 mL/month) 1
• Use of intrauterine devices (associated with increased menstrual blood loss) 1
• Previous diagnosis of iron-deficiency anemia 1
• Low dietary iron intake (only 25% of women meet recommended daily allowance) 1
• Restrictive diets (vegetarian, vegan) 1
• High parity (multiple pregnancies) 1

Clinical Presentation

Women with iron deficiency anemia from menstrual blood loss may experience:

• Poor athletic/physical performance 1
• Fatigue
• Cognitive impairment affecting work and school performance 5
• Hair loss
• Restless legs syndrome 6

Diagnosis

When evaluating for iron deficiency anemia related to menstruation:

• Ferritin levels: The most efficient test for diagnosis of iron deficiency 6

  • <15 μg/L indicates definitive iron deficiency
  • 15-45 μg/L indicates likely iron deficiency

  • 150 μg/L makes iron deficiency unlikely even with inflammation 7

• Complete iron panel: Should include CBC with reticulocyte count, serum iron, transferrin, transferrin saturation, and total iron binding capacity 1

• Assessment of menstrual bleeding: Women who report heavy or very heavy menses are significantly more likely to have lower hemoglobin, hematocrit, and ferritin levels 4

Management

For women with iron deficiency anemia related to menstruation:

1. Oral iron supplementation:

   • First-line treatment for most patients with mild-to-moderate iron deficiency 7
   • Recommended daily elemental iron intake:
     • 60-120 mg for nonpregnant women and adolescent girls 7
     • Take with vitamin C to enhance absorption
     • Avoid taking with calcium, fiber, tea, or coffee 7

2. Consider IV iron when:

   • No response to oral iron therapy after 4-8 weeks
   • Intolerance to oral iron due to gastrointestinal side effects
   • Hemoglobin below 10 g/dL requiring rapid correction 7

3. Address heavy menstrual bleeding:

   • Evaluation for menorrhagia should be considered in women of reproductive age 7
   • Oral contraceptives may reduce menstrual blood loss and decrease risk for iron deficiency 1

4. Monitoring:

   • Check hemoglobin and iron studies in 4-8 weeks to assess response
   • Expected hemoglobin rise ≥10 g/L within 2 weeks
   • Continue treatment for 3 months after hemoglobin normalization 7

Prevention

• Regular screening for anemia is indicated for adolescent girls and women of childbearing age during routine medical examinations 1
• Dietary counseling to ensure adequate iron intake (recommended 18 mg/day for women 19-50 years) 1
• Consider iron supplementation for women with known risk factors for iron deficiency

Important Considerations

• Iron deficiency without anemia can still cause symptoms and impair quality of life
• The effects of iron deficiency can extend beyond the affected woman to impact fetal neurodevelopment if pregnancy occurs 5
• The relationship between heavy menstrual bleeding and iron deficiency is often normalized or overlooked by both patients and healthcare providers 5