What is the recommended daily dose of elemental iron (Fe) for pregnant women?

Iron Dosing for Pregnant Women

Pregnant women should receive 30 mg of elemental iron daily starting at the first prenatal visit for routine supplementation, which can be increased to 60-120 mg daily if anemia develops. 1, 2

Routine Supplementation (Prevention)

• Start 30 mg elemental iron daily at the first prenatal visit for all pregnant women as prophylaxis against iron deficiency anemia 1, 2, 3
• This dose is typically provided through standard prenatal vitamins, which contain 30-48 mg of elemental iron 1, 3
• Continue supplementation throughout pregnancy to meet the Institute of Medicine's Recommended Dietary Allowance of 27 mg per day 1, 3
• The 30 mg dose improves maternal iron status and protects infants from iron-deficiency anemia without the negative effects of higher doses 4

Treatment Dosing (When Anemia is Present)

• Increase to 60-120 mg elemental iron daily when treating diagnosed iron deficiency anemia in pregnancy 1, 2, 5
• The specific dose within this range depends on severity of anemia and patient tolerance 2
• Higher doses (60-100 mg daily) are prescribed for populations at increased risk, including non-Hispanic Black and Mexican American women, vegetarians, and those with short interpregnancy intervals 1, 2, 3
• Continue treatment throughout pregnancy and 2-3 months postpartum to replenish iron stores 2, 5

Monitoring Response

• Recheck hemoglobin after 4 weeks of treatment to confirm adequate response 1, 2, 5
• Expected response is hemoglobin increase ≥1 g/dL or hematocrit increase ≥3% 1, 2
• If no response occurs despite compliance, evaluate for other causes such as thalassemia minor or sickle cell trait in women of African, Mediterranean, or Southeast Asian ancestry 1, 5
• Once hemoglobin normalizes for gestational age, decrease to 30 mg daily for maintenance 1

Special Population Adjustments

• Vegetarian women may require almost twice the standard dose due to poor absorption of non-heme iron from plant sources; consider prescribing at the higher end of the range (100-120 mg daily) 1, 2, 3
• Women with gastrointestinal side effects should reduce to 60 mg daily or consider alternate-day dosing 2
• Higher doses above 100 mg are not recommended due to negative effects on mineral absorption, increased oxidative stress, and adverse gastrointestinal symptoms 4, 6

Optimization Strategies

• Take iron at bedtime or between meals to maximize absorption and reduce gastrointestinal side effects 2, 6, 7
• Avoid concurrent calcium supplements and antacids, which decrease iron absorption 5, 3
• Encourage consumption of vitamin C-rich foods to enhance absorption 5
• Counsel patients that darkening of stool is expected and not harmful 1, 3

Common Pitfalls

• Do not routinely prescribe doses above 120 mg, as higher doses increase side effects without improving outcomes and may impair absorption of other essential minerals 4, 6
• Recent evidence shows that even 27 mg daily (the RDA) may be insufficient to prevent iron deficiency in late pregnancy, with 81% developing probable iron deficiency despite meeting 100% of the RDA 8
• Many women with documented iron deficiency fail to receive appropriate supplementation; ensure follow-through when ferritin is <30 μg/L 8

Answer to Multiple Choice Question

The correct answer is A: 1000 micrograms (1 mg) is incorrect. None of the provided options are correct. The recommended dose is 30,000 micrograms (30 mg) for routine supplementation or 60,000-120,000 micrograms (60-120 mg) for treatment of anemia. 1, 2