What is the best management approach for a 24-week pregnant woman, gravida 7, with severe iron deficiency anemia (hemoglobin level of 6)?

Management of Severe Anemia in Pregnancy at 24 Weeks

For a 24-week pregnant woman with hemoglobin of 6 g/dL, intravenous iron is the preferred treatment to rapidly correct severe anemia and prevent maternal and fetal complications, with oral iron reserved only for mild cases. 1, 2, 3

Immediate Treatment Approach

Intravenous iron should be initiated immediately because:

• Hemoglobin <9 g/dL in pregnancy requires urgent medical evaluation and aggressive treatment 1
• Severe anemia (Hb 6 g/dL) poses significant risks including maternal hypoxia, heart failure, preterm delivery, low birth weight, and fetal bradycardia 2, 4
• IV iron during second and third trimesters is specifically indicated and safe, with published studies showing no adverse maternal or fetal outcomes 2, 3
• IV iron increases hemoglobin more rapidly than oral iron (rising from 7.3 to 9.9 g/dL by day 5 versus no change with oral iron) 5

Specific IV Iron Protocol

Administer iron sucrose (Venofer) 200 mg intravenously on days 1 and 3 2, 5:

• Iron sucrose is FDA-approved for use in pregnancy and has established safety data after the first trimester 2
• Two doses of 200 mg given 2 days apart effectively treats severe postpartum anemia, and the same approach applies to antepartum severe anemia 5
• Alternative high-dose formulations like ferric carboxymaltose (500-1000 mg single infusion) can replace iron deficits in 1-2 infusions 1, 6
• All IV iron must be administered in medical facilities with resuscitation equipment available due to rare risk of severe hypersensitivity reactions and potential fetal bradycardia 2

Why Oral Iron Is Inadequate Here

Oral iron should NOT be first-line treatment at this severity level because:

• Oral iron shows no hemoglobin improvement by day 5, whereas IV iron increases Hb by 2.6 g/dL in the same timeframe 5
• With Hb of 6 g/dL, the patient is at immediate risk for maternal hypoxia and cardiac complications requiring rapid correction 4
• Standard oral dosing (60-120 mg elemental iron daily) is appropriate only for mild anemia (Hb >9 g/dL) 1
• Pregnant women with Hb <9 g/dL specifically require referral for further medical evaluation, not routine oral supplementation 1

Expected Response and Monitoring

Check hemoglobin at 5 days and 2 weeks 5:

• Expect Hb rise of approximately 2.5-3 g/dL by day 5 with IV iron 5
• Ferritin levels rise rapidly and remain significantly higher with IV iron compared to oral iron throughout treatment 5
• Continue monitoring until Hb reaches at least 10 g/dL, then maintain with oral iron 60-120 mg daily for remainder of pregnancy 1

Critical Safety Considerations

Monitor for severe hypersensitivity reactions during IV iron administration 2:

• Severe reactions including circulatory failure and shock can occur, potentially causing fetal bradycardia especially in second and third trimesters 2
• Healthcare providers must be trained to manage anaphylactic reactions 2
• Despite these risks, published randomized controlled trials show no association between IV iron and adverse developmental outcomes when used after first trimester 2

Identify Underlying Cause

Investigate the source of severe iron deficiency while treating 1, 3:

• Assess dietary iron intake and menstrual history prior to pregnancy 1
• Screen for celiac disease with antiendomysial antibody and IgA if malabsorption suspected 1
• Evaluate for gastrointestinal blood loss if no obvious gynecologic cause 1
• Consider H. pylori testing if poor response to treatment 7

Common Pitfalls to Avoid

• Do not use oral iron as first-line treatment when Hb <9 g/dL - this delays necessary rapid correction and increases maternal-fetal risk 1, 4
• Do not delay IV iron while awaiting diagnostic workup - treat severe anemia immediately while investigating cause 1
• Do not discharge without ensuring IV iron administration - outpatient oral iron is inadequate for this severity 5
• Do not use multiple daily oral iron doses - if oral iron is eventually used for maintenance, once-daily dosing is superior 1