What is the recommended treatment for anemia in pregnant women?

Treatment of Anemia in Pregnancy

For pregnant women with anemia, prescribe oral iron supplementation at 60-120 mg of elemental iron daily, which remains the first-line treatment despite insufficient evidence linking it to improved maternal or infant health outcomes. 1, 2

Screening and Diagnosis

• Screen all pregnant women at booking and again at 28 weeks using a full blood count, or hemoglobin/hematocrit measurement where FBC is unavailable. 3
• Diagnose anemia when hemoglobin is <11 g/dL in all trimesters, recognizing that physiologic hemodilution during pregnancy makes precise diagnosis challenging. 3, 4
• Measurement of serum hemoglobin or hematocrit is the primary screening test, though its sensitivity and specificity for detecting iron deficiency anemia in pregnancy are unknown. 4
• Serum ferritin has limited utility during pregnancy as it decreases in late pregnancy despite adequate iron stores and increases during inflammation. 4

Treatment Algorithm by Severity

Mild-to-Moderate Anemia (Hemoglobin 7.0-10.9 g/dL)

• Prescribe 60-120 mg of elemental iron daily as oral supplementation, which improves hemoglobin and ferritin levels even though evidence for clinical outcomes remains inadequate. 1, 2
• Continue treatment for 2-3 months after hemoglobin normalizes to replenish iron stores—a critical step often missed in practice. 2
• Provide dietary counseling emphasizing iron-rich foods (meat, poultry, fortified cereals) and factors enhancing absorption. 1, 4
• Reassess hemoglobin after 4 weeks, expecting an increase of ≥1 g/dL in hemoglobin or ≥3% in hematocrit. 1, 2

Severe Anemia with Presyncope

• Hospitalize immediately when presyncope is present, as this indicates significant cardiovascular compromise requiring hemodynamic stabilization. 1
• Assess for acute hemorrhage, particularly placental complications in second and third trimesters. 1
• Obtain urgent hemoglobin/hematocrit testing to guide immediate management decisions. 1

Treatment Failure or Non-Response

• If anemia persists after 4 weeks of compliant therapy, order additional testing including MCV, RDW, and serum ferritin. 2
• Consider hemoglobinopathies, particularly in women of African, Mediterranean, or Southeast Asian ancestry. 2
• Investigate for underlying bleeding sources if anemia is disproportionate to gestational age. 1

Route of Administration Considerations

Oral iron is preferable to parenteral therapy for most cases, despite parenteral routes producing better hematological indices. 5, 6

Oral Iron

• Produces frequent gastrointestinal side effects (nausea, constipation, diarrhea) that are self-limited and transient. 4, 6
• Lower doses (60 mg) may be as effective as higher doses (120 mg) with fewer side effects, showing a dose-response relationship for adverse effects. 4, 6
• Side effects also include darkening of urine/stool and tooth/gum staining. 4

Parenteral Iron

• Intramuscular and intravenous routes enhance hematological response compared to oral iron. 6
• Concerns exist about serious adverse effects: venous thrombosis and severe allergic reactions with IV iron; significant pain, discoloration, and allergic reactions with IM iron. 6
• Insufficient data on adverse effects limits routine recommendation despite better laboratory responses. 4, 6

Special Populations and Considerations

High-Risk Groups

• Non-Hispanic Black and Mexican American women have higher prevalence rates of iron deficiency than white women. 4
• Women with parity ≥2 are at increased risk. 4
• Vegetarian women may require nearly double the iron supplementation (up to 240 mg daily) due to poor absorption of non-heme iron from plant sources. 1

Additional Risk Factors

• Diet lacking iron-rich foods (vegetarian diets without adequate iron sources). 4
• Gastrointestinal disease or medications decreasing iron absorption (e.g., antacids). 4
• Short interpregnancy intervals. 4

Folic Acid Supplementation

• Folic acid is indicated for megaloblastic anemias of pregnancy, as requirements increase markedly during pregnancy. 7
• Routine iron and folic acid supplementation (either alone or as multiple micronutrient supplements) is recommended during pregnancy. 3
• Caution: Folic acid in doses >0.1 mg daily may obscure pernicious anemia by alleviating hematologic manifestations while neurologic complications progress. 7

Critical Evidence Gaps and Clinical Reality

The USPSTF gives an "I" statement (insufficient evidence) for both screening and routine supplementation, concluding that evidence is inadequate to assess the balance of benefits and harms. 4

What the Evidence Shows:

• No studies demonstrate that screening or treating iron deficiency anemia improves maternal or infant health outcomes such as preterm delivery, cesarean delivery, infant mortality, or low birth weight. 4
• Iron supplementation consistently improves intermediate hematological indices (hemoglobin, ferritin levels) but clinical significance remains unclear. 4
• No studies directly assess whether improving iron status through treatment translates to better health outcomes—a critical gap. 4

Despite Insufficient Evidence:

• Anemia affects 32 million pregnant women globally, contributing to >115,000 maternal deaths and 591,000 perinatal deaths annually. 3
• Severe anemia has very serious consequences for mothers and babies, though controversy exists about treating mild-to-moderate anemia. 6
• In clinical practice, screening and supplementation are common (97% of pregnant women receiving prenatal care in 1988 were advised to take supplements; 77% reported using supplements in 1996-2006). 4

Common Pitfalls to Avoid

• Do not stop iron supplementation when hemoglobin normalizes—continue for 2-3 additional months to replenish stores. 2
• Do not assume all anemia is iron-deficiency—evaluate non-responders thoroughly for other causes. 2
• Do not overlook the need for B12 assessment when folate deficiency is suspected, as folic acid can mask pernicious anemia's hematologic manifestations while neurologic damage progresses. 7
• Do not use high-dose folic acid (>0.1 mg) without ruling out B12 deficiency to prevent masking pernicious anemia. 7