What is the treatment for iron deficiency anemia in a pregnant patient at 39 weeks gestation with a ferritin level indicating iron deficiency?

Treatment for Iron Deficiency Anemia in Late Pregnancy (Week 39)

For a pregnant patient at 39 weeks gestation with a ferritin level of 8, oral iron supplementation at a dose of 60-120 mg of elemental iron daily is recommended until delivery, with dietary counseling to enhance iron absorption. 1

Diagnosis Assessment

• A ferritin level of 8 in the third trimester clearly indicates iron deficiency anemia, as values below 30 ng/mL are diagnostic of iron deficiency
• At 39 weeks gestation, this requires prompt treatment to prevent adverse maternal and fetal outcomes
• Additional evaluation should include:
  • Hemoglobin level to assess severity of anemia
  • Assessment for symptoms (fatigue, dyspnea, exercise intolerance)

Treatment Algorithm

First-line Treatment

• Oral iron supplementation:
  • Dosage: 60-120 mg of elemental iron daily 2, 1
  • Common formulation: Ferrous sulfate 325 mg (containing approximately 65 mg elemental iron)
  • Timing: Best absorbed on empty stomach or with vitamin C-containing foods
  • Continue until delivery and into postpartum period

Dietary Recommendations

• Counsel patient to consume iron-rich foods:
  • Red meat, poultry, fish
  • Beans, lentils, tofu
  • Dark leafy greens
  • Iron-fortified cereals and breads
• Enhance absorption by consuming vitamin C-rich foods with meals
• Avoid calcium supplements, tea, coffee, and dairy products within 2 hours of iron supplements as they inhibit absorption 1

Monitoring and Follow-up

• Monitor hemoglobin response (expect approximately 1 g/dL increase after 4 weeks of compliant therapy) 1
• Continue iron supplementation through delivery
• Recheck ferritin levels 4-6 weeks postpartum to ensure adequate repletion of iron stores 1
• Full restoration of iron stores may take 2-3 months, highlighting the importance of continued supplementation 1

Special Considerations for Late Pregnancy

• At 39 weeks gestation, treatment is particularly important as approximately 80% of fetal iron accrues in the last trimester 1
• Given the advanced gestational age, there is limited time before delivery to correct maternal iron stores
• Continue iron supplementation into the postpartum period to ensure adequate iron stores for breastfeeding and maternal recovery

Alternative Treatment Options

For Severe Anemia or Poor Response to Oral Iron

• If hemoglobin <7 g/dL: Consider blood transfusion 1
• If hemoglobin 7-9.9 g/dL: Consider intravenous iron supplementation 1, 3
• Intravenous iron is indicated for:
  • Oral iron intolerance
  • Poor absorption
  • Ongoing blood loss
  • Need for rapid repletion before delivery 1, 3

Common Pitfalls and Caveats

1. Side effect management: Oral iron commonly causes gastrointestinal side effects (nausea 29-63%, constipation 4-29%) 1

   • Taking with food may reduce side effects but decrease absorption
   • Consider stool softeners for constipation

2. Dosing schedule: If side effects are significant, alternate-day dosing may improve tolerance while maintaining efficacy 3

3. Monitoring: Don't rely solely on hemoglobin improvement; ferritin levels should be monitored to ensure replenishment of iron stores 1

4. Duration: Treatment should not be discontinued when hemoglobin normalizes but should continue to replenish iron stores (ferritin >30 μg/L) 1

5. Postpartum continuation: Iron supplementation should continue postpartum, especially if anemia persists or blood loss during delivery was significant 2, 1

While the USPSTF found insufficient evidence to recommend for or against routine iron supplementation during pregnancy 2, the American College of Obstetricians and Gynecologists and the Centers for Disease Control and Prevention provide clear guidance for treating established iron deficiency anemia during pregnancy, particularly in the third trimester 2, 1.