What are the guidelines for managing anemia in pregnant women?

Management of Anemia in Pregnancy

All pregnant women should be screened for anemia at the first prenatal visit using hemoglobin or hematocrit, and all pregnant women should start 30 mg/day of oral elemental iron supplementation at the first prenatal visit regardless of anemia status. 1, 2

Screening Protocol

• Screen at first prenatal visit using hemoglobin (Hb) or hematocrit (Hct) measurement 1, 2
• Repeat screening at 24-28 weeks gestation to detect anemia developing in later pregnancy 2
• Confirm positive screening with repeat Hb or Hct before initiating treatment 1
• Use gestational age-specific anemia criteria when interpreting results, as physiologic hemodilution occurs during pregnancy 1

Universal Supplementation (Primary Prevention)

• Start 30 mg/day of elemental iron at the first prenatal visit for all pregnant women, regardless of anemia status 1, 2
• Encourage iron-rich foods including meat, poultry, fortified cereals, and foods that enhance iron absorption 1, 2
• Provide dietary counseling emphasizing that vegetarian women may require nearly double the iron intake due to poor absorption of non-heme iron compared to heme iron from meat 1, 3

Treatment of Confirmed Anemia

Mild to Moderate Anemia (Hb ≥9.0 g/dL or Hct ≥27.0%)

• Prescribe 60-120 mg/day of elemental iron orally 1, 2
• Make presumptive diagnosis of iron deficiency anemia and begin treatment immediately in non-acutely ill pregnant women without waiting for additional testing 1, 2
• Provide dietary counseling on correcting iron deficiency through diet 1, 2

Severe Anemia (Hb <9.0 g/dL or Hct <27.0%)

• Refer to a physician familiar with anemia in pregnancy for further medical evaluation 1
• Consider intravenous iron therapy for severe anemia, intolerance to oral iron, or lack of response to oral iron 1, 2

Monitoring Treatment Response

• Reassess Hb or Hct after 4 weeks of treatment 1, 2
• Expected response: Hb increase ≥1 g/dL or Hct increase ≥3% 1, 2

If No Response After 4 Weeks

• Verify compliance with iron supplementation regimen and confirm absence of acute illness 1, 2
• Perform additional testing: mean corpuscular volume (MCV), red cell distribution width (RDW), and serum ferritin 1, 2
• Consider alternative diagnoses in women of African, Mediterranean, or Southeast Asian ancestry, as mild anemia unresponsive to iron may indicate thalassemia minor or sickle cell trait 1

Dose Adjustment During Pregnancy

• Once Hb or Hct normalizes for gestational age, reduce iron to 30 mg/day for maintenance 1, 2
• If Hb >15.0 g/dL or Hct >45.0% in second or third trimester, evaluate for poor blood volume expansion and potential pregnancy complications 1, 2

Intravenous Iron Therapy

• Consider IV iron for: severe anemia, intolerance to oral iron, or lack of response to oral iron after 4 weeks despite confirmed compliance 1, 2
• Before switching to IV iron: confirm compliance with oral regimen and rule out other causes of iron-refractory anemia 2
• Ferric carboxymaltose is preferred due to rapid effectiveness and better tolerability 2
• Monitor for severe hypersensitivity reactions including anaphylaxis and circulatory failure, which may cause fetal bradycardia especially in second and third trimesters 4

Common Pitfalls to Avoid

• Do not assume compliance without verification, as gastrointestinal side effects (nausea, constipation, diarrhea) commonly lead to treatment discontinuation 1, 3
• Do not use serum iron measurement alone as a diagnostic marker; serum ferritin has the highest sensitivity and specificity for diagnosing iron deficiency 5
• Do not overlook dietary factors: women taking antacids or proton pump inhibitors have decreased iron absorption 1
• Do not forget high-risk groups: Non-Hispanic Black and Mexican American women, women with parity ≥2, vegetarians, and those with short interpregnancy intervals have higher prevalence of iron deficiency 1

Postpartum Management

• Screen at-risk women at 4-6 weeks postpartum using Hb or Hct with non-pregnant anemia criteria 1, 2
• Risk factors for postpartum anemia: anemia persisting through third trimester, excessive blood loss at delivery, multiple birth 1, 2
• Continue iron supplementation throughout pregnancy and postpartum period to prevent recurrence 2
• Stop supplemental iron at delivery if no risk factors for anemia are present 1

Special Populations

• Vegetarian women may require nearly double the iron supplementation (up to 54 mg/day) due to lower bioavailability of non-heme iron 1, 3
• Women with gastrointestinal disease or on medications that decrease iron absorption (antacids, PPIs) require closer monitoring 1
• Adolescent pregnant women (≤18 years) have particularly high rates of iron deficiency anemia (42-59% in placebo groups) and benefit substantially from supplementation 6