Should a 20-year-old female with abnormal uterine bleeding (AUB) and anemia take iron supplements while on oral birth control?

Yes, Iron Supplementation is Indicated

This 20-year-old woman with AUB and anemia (hemoglobin 9.1 g/dL, hematocrit 29.9%) should receive oral iron supplementation at 60-120 mg elemental iron daily in addition to her oral contraceptive, as all patients with iron deficiency anemia require iron supplementation to correct anemia and replenish body stores. 1

Rationale for Iron Supplementation

Anemia Severity Assessment

• Her hemoglobin of 9.1 g/dL and hematocrit of 29.9% meet diagnostic criteria for anemia in nonpregnant women 1
• While not critically severe (threshold for urgent physician referral is Hb <9.0 g/dL in pregnancy guidelines), this level warrants treatment 1
• AUB is a leading cause of iron deficiency anemia in women of reproductive age, and can lead to severe depletion if untreated 2, 3

Treatment Protocol

Oral iron dosing:

• Prescribe 60-120 mg elemental iron daily (most commonly ferrous sulfate 200 mg three times daily, ferrous gluconate, or ferrous fumarate) 1
• Continue iron supplementation for three months after correction of anemia to replenish iron stores 1

Monitoring response:

• Recheck hemoglobin after 3-4 weeks; expect an increase of approximately 2 g/dL 1
• If hemoglobin fails to rise by 1 g/dL (or hematocrit by 3%) after 4 weeks despite compliance, consider further evaluation including MCV, RDW, and serum ferritin 1
• Common causes of treatment failure include poor compliance, continued blood loss from ongoing AUB, or malabsorption 1

Role of Oral Contraceptives

Complementary but Insufficient Alone

• Oral contraceptives reduce menstrual blood loss and independently decrease risk of anemia, but do not replace the need for iron supplementation when anemia is already present 4
• Some oral contraceptives contain 25 mg elemental iron in placebo tablets, but this dose is insufficient to treat established anemia 4
• One randomized trial found no significant difference in hemoglobin or iron status between iron-containing oral contraceptives and standard formulations after 12 months 4

Dual Therapy Approach

• The oral contraceptive addresses the underlying cause (AUB) by reducing menstrual blood loss 2, 5
• Iron supplementation corrects the existing anemia and replenishes depleted stores 1
• Both interventions are necessary: hormonal therapy alone will not rapidly correct established anemia 5

Practical Considerations

Enhancing Absorption

• Consider adding ascorbic acid (vitamin C) if response to iron is poor, as it enhances iron absorption 1
• Counsel on dietary sources of iron and foods that enhance absorption 1

Managing Side Effects

• Common side effects include nausea, constipation, and diarrhea, but these are typically mild and transient 1
• If oral iron is not tolerated, try alternative formulations (ferrous gluconate or fumarate instead of sulfate, or liquid preparations) 1
• Parenteral iron should only be used after failure of at least two oral preparations 1

Follow-up Strategy

• Monitor hemoglobin and MCV at three-month intervals for one year, then annually 1
• If anemia recurs despite adequate initial treatment, further investigation for underlying bleeding disorders (particularly von Willebrand disease in adolescents with AUB since menarche) or other causes may be warranted 2

Common Pitfalls to Avoid

• Do not rely on oral contraceptives alone to treat established anemia—they prevent future iron loss but do not rapidly correct existing deficiency 4
• Do not stop iron supplementation once hemoglobin normalizes—continue for three months to replenish stores 1
• Do not assume compliance—treatment failure is most commonly due to poor adherence 1
• Do not overlook bleeding disorders—approximately 20% of adolescents with heavy menstrual bleeding have an underlying coagulation disorder 2