What is the appropriate diagnosis and management for a pregnant woman with hemoglobin (Hb) 8.7 g/dL (moderate anemia)?

Management of Moderate Anemia in Pregnancy (Hemoglobin 8.7 g/dL)

Initiate oral iron therapy immediately at 60-120 mg elemental iron daily, as this hemoglobin of 8.7 g/dL represents moderate anemia requiring therapeutic intervention beyond routine supplementation. 1, 2

Diagnosis and Classification

This patient has moderate anemia (hemoglobin 7.0-9.9 g/dL), which requires both treatment and investigation of the underlying cause 1, 2. The hemoglobin of 8.7 g/dL falls well below the pregnancy threshold of <10.5 g/dL in the second or third trimester 1, 2.

Initial Diagnostic Workup

Obtain the following laboratory tests immediately to determine the etiology:

• Mean corpuscular volume (MCV) to differentiate microcytic from macrocytic causes 1, 2
• Red cell distribution width (RDW) to assess heterogeneity of red cell size 1
• Serum ferritin to confirm iron deficiency (most common cause in pregnancy) 1, 2
• Complete blood count if not already performed 1, 2

If the MCV is mildly low or normal with this moderate anemia, iron deficiency is the most likely diagnosis and empiric treatment is appropriate 2. However, a very low MCV (<70 fL) warrants hemoglobin electrophoresis to exclude thalassemia, particularly in patients of African, Mediterranean, or Southeast Asian ancestry 1.

Treatment Protocol

Oral Iron Therapy (First-Line)

Start 60-120 mg elemental iron daily immediately 1, 2. This therapeutic dose is higher than the 30 mg/day used for routine prophylaxis 1.

Key evidence on dosing strategy: Recent data demonstrates that intermittent dosing (every other day) is as effective as daily dosing with fewer gastrointestinal side effects 1. If the patient experiences significant side effects (nausea, constipation, abdominal discomfort), switch to alternate-day dosing rather than discontinuing therapy 1.

Common oral iron formulations include:

• Iron sulfate
• Ferrous fumarate
• Iron polymaltose complex 3

Expected Response and Monitoring

• Recheck hemoglobin in 1-2 weeks after initiating therapy 1
• Expect an increase of at least 1 g/dL after 4 weeks of treatment 1
• If no response after 4 weeks, proceed to further evaluation with MCV, RDW, and ferritin if not already done 1
• Once hemoglobin normalizes for gestational age, decrease to maintenance dose of 30 mg/day 1

When Oral Iron Fails

If the patient cannot tolerate oral iron, cannot absorb it, or does not respond after 4 weeks, intravenous iron is the preferred alternative 2. Contemporary IV iron formulations have rare allergic reactions 2.

Transfusion Threshold

Blood transfusion is NOT indicated at hemoglobin 8.7 g/dL 3. Transfusion is reserved for:

• Hemoglobin <7.0 g/dL 1, 3
• Cardiorespiratory compromise regardless of hemoglobin level 3
• Clinical symptoms of hemodynamic instability 1

Each unit of packed red blood cells raises hemoglobin by approximately 1.5 g/dL 1.

Nutritional Counseling

Provide specific dietary guidance:

• Iron-rich foods: red meat, poultry, fish, legumes, fortified cereals 1
• Absorption enhancers: vitamin C-rich foods (citrus, tomatoes, peppers) taken with iron 1
• Avoid absorption inhibitors: calcium supplements, tea, coffee within 2 hours of iron intake 1

Obstetric Implications and Monitoring

Moderate anemia at this level is associated with:

• Increased risk of blood transfusion at delivery 2
• Potential adverse fetal and neonatal outcomes (though causality not definitively established) 2

Continue close monitoring throughout pregnancy with repeat complete blood counts to ensure adequate response and prevent progression to severe anemia 1, 2.

Common Pitfalls

• Do not delay treatment while waiting for ferritin results—empiric iron therapy is both diagnostic and therapeutic for likely iron deficiency 2
• Do not use transfusion as first-line therapy at this hemoglobin level; it is reserved for severe anemia or hemodynamic compromise 1, 3
• Do not discontinue iron if mild gastrointestinal side effects occur; switch to alternate-day dosing instead 1
• Do not forget to screen again at 24-28 weeks if this is first-trimester anemia, as recommended screening intervals require reassessment 1