What are the guidelines for managing iron deficiency anemia in pregnancy?

Management of Anemia in Pregnancy

All pregnant women should receive 30 mg/day of oral elemental iron starting at the first prenatal visit, and if anemia is diagnosed, increase to 60-120 mg/day of elemental iron with dietary counseling. 1, 2

Screening Protocol

• Screen all pregnant women for anemia at the first prenatal visit and again at 24-28 weeks gestation using hemoglobin or hematocrit testing. 2
• Confirm positive screening results with repeat hemoglobin or hematocrit before initiating treatment. 1, 2
• In non-acutely ill pregnant women, make a presumptive diagnosis of iron deficiency anemia and begin treatment immediately without waiting for additional testing. 2, 3

Anemia thresholds vary by trimester: hemoglobin <11.0 g/dL in the first trimester and <10.5 g/dL in the second or third trimester. 4

Treatment Algorithm

Initial Management

• Start all pregnant women on 30 mg/day of oral elemental iron at the first prenatal visit as primary prevention. 1, 2
• For diagnosed anemia, prescribe 60-120 mg/day of elemental iron orally. 1, 2, 3
• Provide dietary counseling on iron-rich foods and factors that enhance iron absorption. 1, 2, 3

Important caveat: Vegetarian women may require nearly double the iron supplementation due to lower absorption of non-heme iron. 2, 3

Monitoring Response

• Reassess hemoglobin or hematocrit after 4 weeks of treatment. 2, 3
• Expected response is an increase of ≥1 g/dL in hemoglobin or ≥3% in hematocrit. 2
• If no response after 4 weeks despite compliance and absence of acute illness, perform additional testing including mean corpuscular volume, red cell distribution width, and serum ferritin. 1, 2

Common pitfall: In women of African, Mediterranean, or Southeast Asian ancestry, mild anemia unresponsive to iron therapy may be due to thalassemia minor or sickle cell trait. 1

Dose Adjustment

• Once hemoglobin or hematocrit normalizes for gestational age, reduce iron dose to 30 mg/day for maintenance. 1, 2
• If hemoglobin is >15.0 g/dL or hematocrit is >45.0% in the second or third trimester, evaluate for poor blood volume expansion and potential pregnancy complications. 1, 2

Severe Anemia Management

• If hemoglobin is <9.0 g/dL or hematocrit is <27.0%, refer to a physician familiar with anemia during pregnancy for further medical evaluation. 1

Intravenous Iron Therapy

Consider intravenous iron for pregnant women with severe anemia, intolerance to oral iron, or lack of response to oral iron after 4 weeks despite compliance. 2

When to Switch to IV Iron

• Before switching, confirm compliance with oral iron regimen and rule out other causes of iron-refractory anemia. 2, 3
• Ferric carboxymaltose is the preferred intravenous iron option due to its rapid effectiveness and better tolerability. 2, 5
• Intravenous iron sucrose is an effective alternative, with evidence showing a mean hemoglobin increase of 7.17 g/L compared to oral ferrous sulfate. 6

Evidence note: A 2021 network meta-analysis of 53 trials demonstrated that intravenous iron sucrose and ferric carboxymaltose were superior to oral ferrous sulfate for improving hemoglobin levels. 6

Safety Considerations

• Gastrointestinal side effects (nausea, vomiting, altered bowel movements) are common with oral iron but generally self-limited. 2
• Allergic reactions with contemporary IV iron formulations are rare, though close surveillance during administration is recommended. 7, 4

Postpartum Management

• Screen women at risk for anemia at 4-6 weeks postpartum using hemoglobin or hematocrit. 1, 2, 3
• Risk factors include anemia persisting through the third trimester, excessive blood loss at delivery, and multiple birth. 1, 2
• Treatment and follow-up for postpartum iron deficiency anemia are the same as for nonpregnant women. 1
• If no risk factors for anemia are present, stop supplemental iron at delivery. 1

For postpartum women with hemoglobin <95 g/L who do not respond to oral iron, intravenous ferric carboxymaltose is the recommended treatment. 5, 7