Treatment of Iron Deficiency Anemia in Pregnancy
For iron deficiency anemia in pregnancy, start oral iron supplementation at 60-120 mg of elemental iron daily, monitor hemoglobin response after 4 weeks, and switch to intravenous iron if oral therapy fails or in cases of severe anemia (hemoglobin <90 g/L) beyond 14 weeks gestation. 1, 2
Initial Diagnosis and Treatment Approach
Screening and Diagnosis
- Screen all pregnant women for anemia at the first prenatal visit using hemoglobin or hematocrit measurements 1
- A presumptive diagnosis of iron deficiency anemia can be made and treatment initiated immediately if the woman is not acutely ill 1, 2
- Serum ferritin is a helpful adjunct for diagnosis, with iron deficiency defined as ferritin <30 μg/L 3
First-Line Treatment: Oral Iron
- The American College of Obstetricians and Gynecologists recommends 60-120 mg/day of elemental iron as first-line treatment 1, 2
- Take oral iron between meals to maximize absorption 4
- Avoid taking calcium supplements and antacids at the same time as iron, as they decrease absorption 5
- Counsel patients about consuming iron-rich foods (meat, poultry, iron-fortified grains) and foods that enhance absorption 1
Monitoring Response to Treatment
- Recheck hemoglobin/hematocrit after 4 weeks of treatment 1
- An adequate response is defined as hemoglobin increase ≥1 g/dL or hematocrit increase ≥3% 1
- If oral iron fails to increase hemoglobin within 2 weeks, confirm compliance and rule out other causes of anemia before switching to IV iron 2, 4
Algorithm for Severe Anemia or Oral Iron Failure
Indications for Intravenous Iron
Intravenous iron should be considered in three specific scenarios 4, 3:
- As second-line option: When oral iron fails to increase hemoglobin within 2 weeks despite confirmed compliance 2, 4
- As first-line option for profound anemia: Hemoglobin <90 g/L in any trimester beyond 14 weeks gestation 4
- As first-line option in third trimester: For any iron deficiency anemia diagnosed late in pregnancy when rapid correction is needed 4, 6
IV Iron Dosing and Safety
- Total dose typically ranges from 600-1,200 mg 4
- IV iron is considered safe in the second and third trimester, with limited experience in the first trimester 4
- Modern generations of IV iron (such as ferric carboxymaltose) demonstrate shorter infusion times and improved safety profiles 6, 3
- While anaphylactic reactions are extremely rare with non-dextran products, close surveillance during administration is recommended 3
Special Populations Requiring Higher Doses
High-Risk Groups
- Vegetarian women: May require almost twice as much iron (up to 100 mg daily) due to poor absorption of non-heme iron from plant sources 5, 2
- Non-Hispanic Black and Mexican American women: Have higher prevalence rates of iron deficiency and require closer monitoring 5
- Women with short intervals between pregnancies: Are at higher risk and may need 60-100 mg elemental iron daily 5
Postpartum Management
- Screen women with risk factors (third trimester anemia or excessive blood loss at delivery) for anemia at 4-6 weeks postpartum 1, 2
- For mild postpartum iron deficiency anemia, continue oral iron therapy 3
- For moderate-to-severe postpartum anemia (hemoglobin <95 g/L), administer intravenous iron 3
- Continue iron supplementation throughout the postpartum period to prevent recurrence 2
Common Pitfalls to Avoid
- Failing to identify high-risk women who need increased supplementation beyond standard prenatal vitamins 5
- Not confirming compliance before labeling oral iron as ineffective 2
- Delaying IV iron in cases of profound anemia or late third trimester diagnosis when rapid correction is essential 4
- Ignoring gastrointestinal side effects: Many side effects overlap with normal pregnancy symptoms, but poor tolerance leads to non-compliance 7, 8
- Not screening postpartum: Women at risk need follow-up at 4-6 weeks to prevent persistent anemia 1, 2