What are the guidelines for managing anemia in pregnant women?

Management of Anemia in Pregnant Women

All pregnant women should be screened for anemia at the first prenatal visit and again at 24-28 weeks gestation using hemoglobin or hematocrit testing, with universal prophylactic iron supplementation of 30 mg/day of elemental iron started at the first prenatal visit. 1

Screening Protocol

• Screen all pregnant women at the first prenatal visit using hemoglobin (Hb) or hematocrit (Hct) measurement 2, 1
• Repeat screening at 24-28 weeks gestation 1
• Confirm any positive screening result with a repeat Hb or Hct test before initiating treatment 2, 1
• Use trimester-specific thresholds to define anemia, as physiologic hemodilution occurs during pregnancy 2

Diagnostic Thresholds and Workup

• If Hb is less than 9.0 g/dL or Hct is less than 27.0%, refer to a physician familiar with anemia during pregnancy for further evaluation 2, 1
• In non-acutely ill pregnant women with confirmed anemia, make a presumptive diagnosis of iron deficiency anemia and begin treatment immediately without waiting for additional testing 1
• Additional laboratory testing (MCV, RDW, serum ferritin) is reserved for cases that fail to respond to treatment after 4 weeks 2, 1

Treatment Algorithm

Primary Prevention

• Start 30 mg/day of oral elemental iron at the first prenatal visit for all pregnant women 2, 1
• Provide dietary counseling on iron-rich foods and foods that enhance iron absorption 2, 1

Treatment of Established Anemia

• Prescribe 60-120 mg/day of elemental iron orally for mild to moderate anemia 2, 1
• Common formulations include ferrous sulfate, ferrous fumarate, or iron polymaltose complex 3
• Continue dietary counseling alongside supplementation 2, 1

Monitoring Response to Treatment

• Reassess Hb or Hct after 4 weeks of treatment 2, 1
• Expected response is an increase of ≥1 g/dL in Hb or ≥3% in Hct 1
• Once Hb or Hct normalizes for gestational age, reduce iron dose to 30 mg/day for maintenance 2, 1

Management of Treatment Failure

If anemia does not respond after 4 weeks despite compliance and absence of acute illness:

• Perform additional testing including MCV, RDW, and serum ferritin 2, 1
• Consider alternative diagnoses in women of African, Mediterranean, or Southeast Asian ancestry (thalassemia minor or sickle cell trait) 2, 1
• Switch to intravenous iron therapy for oral iron-refractory cases, severe intolerance, or need for rapid correction 1, 4

Intravenous Iron Therapy

• Ferric carboxymaltose is the preferred intravenous iron preparation due to rapid effectiveness and better tolerability 1, 4
• Dosing: 15 mg/kg body weight up to maximum 750 mg per dose, administered on two occasions separated by at least 7 days, for cumulative dose up to 1,500 mg 4
• Administration time is 15 minutes, significantly more convenient than older preparations 4
• Alternative preparations include iron sucrose (maximum 200 mg per dose, 10-minute infusion) 4
• Intravenous iron sucrose improves Hb by mean difference of 7.17 g/L compared to oral ferrous sulfate 5
• Ferric carboxymaltose improves Hb by mean difference of 8.52 g/L compared to oral ferrous sulfate 5

Special Considerations

• Vegetarian women may require nearly double the iron supplementation due to lower absorption of non-heme iron 1
• Gastrointestinal side effects (nausea, vomiting, altered bowel movements) are common with oral iron but generally self-limited 2, 1
• If Hb is greater than 15.0 g/dL or Hct is greater than 45.0% in the second or third trimester, evaluate for poor blood volume expansion and potential pregnancy complications 2, 1

Postpartum Management

• Screen women at risk for anemia at 4-6 weeks postpartum using Hb or Hct 2, 1
• Risk factors include anemia persisting through the third trimester, excessive blood loss at delivery, and multiple birth 2, 1
• Treatment and follow-up for postpartum iron deficiency anemia are the same as for nonpregnant women 2
• If no risk factors for anemia are present, stop supplemental iron at delivery 2

Common Pitfalls

• Real-world effectiveness of oral iron is lower than expected, with only 36.5% of women showing adequate response after first course and 70.5% by completion of follow-up 6
• Non-responders report more side effects than responders (95% versus 85%), which may impair adherence 6
• Clinicians should have a low threshold for switching to intravenous iron in cases of poor response or intolerance, rather than prolonging ineffective oral therapy 4, 5