How should a 26‑year‑old gravida 3, para 2 woman at 36 weeks' gestation with hemoglobin 8 g/dL, serum ferritin 8 ng/mL and a microcytic‑hypochromic anemia on peripheral smear be managed?

Management of Iron Deficiency Anemia at 36 Weeks Gestation

Initiate intravenous iron therapy immediately as first-line treatment given the severe iron deficiency (ferritin 8 ng/mL), moderate anemia (Hb 8 g/dL), and advanced gestational age (36 weeks) where rapid correction is essential before delivery. 1, 2, 3

Rationale for Intravenous Iron as First-Line Treatment

At 36 weeks gestation with Hb 8 g/dL and ferritin 8 ng/mL, intravenous iron is the appropriate first-line intervention rather than oral iron, based on multiple clinical factors:

• Advanced gestational age requires rapid hemoglobin correction before anticipated delivery at 36-37 weeks, and oral iron cannot achieve adequate repletion in this timeframe 2, 3
• Profound iron deficiency (ferritin 8 ng/mL, well below the 15 ng/mL diagnostic threshold) indicates severely depleted iron stores requiring aggressive replacement 1
• Intravenous iron is superior to oral iron with respect to hematological response and speed of correction 2, 3
• Clinical need for rapid treatment in advanced pregnancy (beyond 34 weeks) is an established indication for intravenous therapy 3

Specific Treatment Protocol

Intravenous Iron Administration

• Administer ferric carboxymaltose 1,000-1,200 mg intravenously as the preferred agent, given its safety profile in second and third trimester and ability to deliver large iron doses in single infusions 4, 2, 3
• Close surveillance during administration is mandatory for all intravenous iron products, though anaphylactic reactions are extremely rare with non-dextran formulations 3
• Expect hemoglobin increase of approximately 0.6 g/dL within 2-4 weeks based on clinical trial data in similar populations 4

Monitoring Parameters

• Recheck hemoglobin within 2 weeks of intravenous iron administration to assess response 2, 3
• Do not measure ferritin within 4 weeks of intravenous iron infusion, as circulating iron interferes with the assay and produces falsely elevated results 5
• Monitor for hypophosphatemia symptoms (fatigue, muscle weakness, bone pain) as a potential adverse effect of ferric carboxymaltose 4

Delivery Planning Considerations

Timing and Coordination

• Plan delivery at 36-37 weeks as recommended for stable patients, with no need for amniocentesis at this gestational age 1
• Coordinate with blood bank given the frequent need for large-volume transfusion in patients with anemia and potential obstetric complications 1
• Optimize hemoglobin before delivery to reduce transfusion risk and improve maternal outcomes 1

Transfusion Thresholds

• Maintain restrictive transfusion threshold of 7-8 g/dL perioperatively unless symptomatic or actively bleeding 1
• Transfusion is associated with increased complications including pulmonary, septic, wound, and thromboembolic events compared to not receiving transfusion 1

Diagnostic Confirmation

The clinical picture confirms iron deficiency anemia:

• Ferritin 8 ng/mL is highly specific for iron deficiency (specificity 0.99 when <15 μg/L) 1, 5
• Microcytic hypochromic anemia on peripheral smear is consistent with iron deficiency 1, 6, 7
• Hemoglobin 8 g/dL represents moderate anemia requiring intervention 1

Common Pitfalls to Avoid

• Do not rely on oral iron alone at this gestational age—insufficient time for adequate response before delivery 2, 3
• Do not delay treatment waiting for oral iron trial—advanced pregnancy requires immediate intervention 2, 3
• Do not check ferritin immediately after IV iron—wait minimum 4 weeks to avoid falsely elevated results 5
• Do not transfuse prophylactically unless hemoglobin drops below 7-8 g/dL or patient becomes symptomatic 1

Alternative Scenario: If Intravenous Iron Unavailable

If intravenous iron is truly unavailable or contraindicated:

• Administer oral ferrous iron 100-200 mg daily between meals to maximize absorption 2, 6
• Recheck hemoglobin after 2 weeks—expect increase of ≥10 g/L if oral therapy effective 2
• Maintain lower threshold for transfusion given limited time for oral iron response 1