What is the recommended treatment for iron deficiency anemia in a pregnant individual in the 3rd trimester?

Treatment for Iron Deficiency Anemia in Third Trimester Pregnancy

The recommended treatment for iron deficiency anemia in a pregnant individual in the 3rd trimester is oral iron supplementation at a dose of 60-120 mg of elemental iron per day. 1

Diagnosis Confirmation

• A presumptive diagnosis of iron deficiency anemia can be made based on low hemoglobin or hematocrit values appropriate for the stage of pregnancy, if the woman is not acutely ill 2, 1
• In the third trimester, hemoglobin below 10.5-11.0 g/dL (depending on the guideline used) is considered anemia 3
• The prevalence of iron deficiency in pregnant women increases significantly in the third trimester, affecting up to 29.5% of women 2

Treatment Algorithm

First-Line Treatment

• Oral iron supplementation at 60-120 mg/day of elemental iron is the recommended first-line treatment 2, 1
• Treatment should be accompanied by dietary counseling to increase consumption of iron-rich foods and foods that enhance iron absorption 2, 1
• Common oral iron preparations include ferrous sulfate, ferrous gluconate, and ferrous fumarate 3

Monitoring Response

• Monitor response to treatment after 4 weeks 2, 1
• An adequate response is defined as a hemoglobin increase of ≥1 g/dL or hematocrit increase of ≥3% 2, 1
• If anemia persists despite compliance with oral iron, further evaluation with additional laboratory tests may be needed, including mean corpuscular volume (MCV), red cell distribution width (RDW), and serum ferritin 2

Alternative Treatment Options

• For patients who cannot tolerate oral iron due to gastrointestinal side effects, intermittent dosing (every other day) may be as effective as daily dosing with fewer side effects 3
• Intravenous (IV) iron should be considered in cases of: 4, 5
  • Oral iron intolerance
  • Poor absorption of oral iron
  • Severe anemia (hemoglobin <8 g/dL) in the third trimester
  • Failure to respond to oral iron therapy

Clinical Considerations

• Compliance with iron supplementation is crucial for effectiveness. Studies show that hemoglobin levels improve significantly only among strictly compliant pregnant women (+0.3 g/dL) but decrease among non-compliant women (-1.4 g/dL) 6
• Non-compliance with iron supplementation is associated with a significantly higher risk of anemia (OR 6.19,95% CI 2.55-15.02) 6
• Gastrointestinal side effects are common with oral iron and can lead to poor adherence 4
• While the Centers for Disease Control and Prevention (CDC) recommends iron supplementation, the U.S. Preventive Services Task Force (USPSTF) found insufficient evidence to determine the balance of benefits and harms of iron supplementation during pregnancy 2

Potential Pitfalls and Caveats

• Excessive iron supplementation leading to high hemoglobin, hematocrit, and ferritin levels has been associated with increased risk of fetal growth restriction, preterm delivery, and preeclampsia 7
• Physiologic anemia of pregnancy (hemodilution) is normal during pregnancy and should not be confused with iron deficiency anemia 2
• Anemia in the third trimester may not be associated with the same adverse outcomes as anemia in early pregnancy 2, 7
• When using serum ferritin to diagnose iron deficiency during pregnancy, remember that ferritin is an acute phase reactant and may be elevated during inflammation, potentially masking iron deficiency 2
• 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 2