Management of Anemia in Pregnancy

Diagnostic Approach

The American College of Obstetricians and Gynecologists recommends screening all pregnant women with hemoglobin and hematocrit at the first prenatal visit, and start low-dose oral iron supplementation (30 mg/day elemental iron) immediately for primary prevention, regardless of anemia status 1
Pregnancy causes physiologic hemodilution that progressively lowers hemoglobin concentration, making diagnosis challenging 2, 3
The diagnostic thresholds for anemia vary by trimester: First trimester, hemoglobin <11.0 g/dL; Second trimester, hemoglobin <10.5 g/dL; Third trimester, hemoglobin <11.0 g/dL 1, 4

Iron deficiency affects 18.6% of pregnant women overall, increasing from 6.9% in the first trimester to 29.5% in the third trimester 2, 5, 4
Risk factors for iron deficiency include Non-Hispanic Black and Mexican American ethnicity, vegetarian diet lacking adequate iron sources, gastrointestinal disease or medications reducing iron absorption, short interpregnancy interval, and parity ≥2 5

For confirmed iron deficiency anemia (Hb <11 g/dL), prescribe 60-120 mg elemental iron daily, taken between meals 6, 4
For iron deficiency without anemia, start 30 mg elemental iron daily 4
For primary prevention in all pregnant women, begin 30 mg elemental iron daily at the first prenatal visit 6, 1
Reassess hemoglobin after 4 weeks of treatment, expecting an increase of ≥1 g/dL or hematocrit increase of ≥3% 6, 4

Refer to a physician familiar with anemia in pregnancy when hemoglobin is <9.0 g/dL or hematocrit is <27.0% 6, 4

Impaired neurocognitive function and mood disturbances can occur even before anemia develops 4
Intrauterine growth restriction, low birth weight, small-for-gestational-age, preterm delivery, stillbirth, early neonatal death, and impaired fetal brain development are potential fetal complications of untreated anemia 4

In pregnant women of Indian or other high‑risk ethnic backgrounds (e.g., African, Mediterranean, Southeast Asian), screening for hemoglobinopathies such as thalassemia and sickle‑cell trait should be performed, especially when anemia does not improve after four weeks of oral iron therapy. 7