How to treat iron deficiency anemia (IDA) with a ferritin level of 8 in a patient at 30 weeks gestation in the 3rd trimester of pregnancy?

Treatment of Iron Deficiency Anemia in Third Trimester Pregnancy with Ferritin of 8

For a pregnant patient at 30 weeks gestation with a ferritin level of 8, oral iron supplementation at a dose of 60-120 mg of elemental iron daily is the recommended treatment. 1

Diagnosis Assessment

• A ferritin level of 8 μg/L in the third trimester confirms iron deficiency anemia (IDA)
• Normal ferritin in pregnancy should be >30 μg/L, with levels <30 μg/L indicating iron deficiency 1, 2
• Third trimester anemia is defined as hemoglobin <10.5 g/dL 1

Treatment Approach

First-Line Treatment

• Oral iron therapy (60-120 mg elemental iron daily) 1
  • Ferrous sulfate is the most common preparation and is safe during pregnancy 1, 3
  • Take between meals or at bedtime to optimize absorption 4
  • Continue until hemoglobin normalizes, then reduce to maintenance dose of 30 mg/day 1

Monitoring Response

• Recheck hemoglobin after 4 weeks of treatment 1
• Expect hemoglobin to increase by approximately 1 g/dL after 4 weeks of compliant therapy 1
• If no improvement after 4 weeks despite compliance (hemoglobin doesn't increase by 1 g/dL), further evaluation is needed 5

Managing Side Effects

• Common gastrointestinal side effects include nausea (29-63%), constipation (4-29%), and abdominal discomfort 1, 3
• Taking iron with meals can minimize gastrointestinal discomfort but may reduce absorption 3
• Low-dose iron supplements (20 mg/day) have been shown to be effective with fewer side effects, but higher doses are needed for treatment of established IDA 6

Alternative Treatment Options

Intravenous Iron Therapy

• Consider IV iron if:
  • Oral iron is not tolerated
  • No response to oral iron after 4 weeks
  • Hemoglobin <7-9.9 g/dL (moderate to severe anemia)
  • Need for rapid correction of anemia late in pregnancy 1, 2
• IV iron formulations that have been studied in pregnancy should be preferred for safety reasons 2

Blood Transfusion

• Reserved for severe anemia (Hb <7 g/dL) with hemodynamic instability 1
• Not typically indicated for Hb >9 g/dL 1

Long-term Considerations

• Continue iron supplementation through delivery and into the postpartum period 1
• 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 even with treatment 1
• Approximately 80% of fetal iron accrues in the last trimester, making treatment during this period particularly important 1

Important Caveats

• Untreated IDA in the third trimester increases risk for preterm delivery and low birth weight 1, 7
• Iron requirements increase significantly during pregnancy due to maternal blood volume expansion and fetal demands 1
• Without supplementation, most pregnant women cannot maintain adequate iron stores during the second and third trimesters 1, 8
• Avoid excessive iron supplementation by monitoring response and adjusting dosage accordingly 1