What is the recommended dose of iron for pregnant women?

Recommended Iron Dose for Pregnant Women

For routine prophylaxis in pregnancy, the recommended dose is 30 mg of elemental iron daily, starting at the first prenatal visit, which corresponds to answer choice A (though the question appears to list doses in units that may need clarification). 1, 2

Standard Supplementation Approach

The evidence-based dosing strategy depends on whether supplementation is for prophylaxis versus treatment:

Prophylactic Supplementation (No Anemia Present)

• Start 30 mg elemental iron daily at the first prenatal visit for routine prevention in all pregnant women 1, 2
• Most prenatal vitamins contain 30-48 mg of elemental iron, which meets this prophylactic requirement 1, 2
• The Institute of Medicine recommends a total daily iron requirement of 27 mg during pregnancy from all sources (diet plus supplements) 1, 2

Treatment Dosing (Iron Deficiency Anemia Diagnosed)

• Prescribe 60-120 mg elemental iron daily when treating confirmed iron deficiency anemia 1, 3
• This therapeutic dose is significantly higher than prophylactic dosing and should be reserved for documented anemia 1, 3

Risk-Stratified Approach

For women at higher risk of iron deficiency (non-Hispanic Black, Mexican American, vegetarian diet, short interpregnancy interval, gastrointestinal disease), consider:

• 60-100 mg elemental iron daily as enhanced prophylaxis 1, 2
• These populations have higher baseline prevalence of iron deficiency and benefit from increased supplementation 1, 2

Clinical Algorithm for Dosing

At first prenatal visit:

1. Screen hemoglobin/hematocrit to assess for anemia 1
2. If no anemia: Start 30 mg elemental iron daily 1, 2
3. If anemia present (Hb <11 g/dL first trimester, <10.5 g/dL second trimester): Start 60-120 mg elemental iron daily 1, 3
4. If high-risk factors present but no anemia: Consider 60-100 mg elemental iron daily 1, 2

After 4 weeks of treatment for anemia:

• Recheck hemoglobin; expect increase of ≥1 g/dL 1, 3
• If hemoglobin normalizes, reduce to maintenance dose of 30 mg daily 1
• If no response despite compliance, evaluate for other causes (thalassemia, sickle cell trait) 1, 3

Important Caveats

Timing and absorption considerations:

• Take iron between meals or at bedtime to maximize absorption and minimize gastrointestinal side effects 2, 3
• Avoid concurrent calcium supplements and antacids, which significantly decrease iron absorption 2, 3
• Vegetarian women may require nearly double the iron intake due to poor absorption of non-heme iron from plant sources 1, 2

Common pitfalls to avoid:

• Do not prescribe therapeutic doses (60-120 mg) for routine prophylaxis, as higher doses increase gastrointestinal side effects without additional benefit in non-anemic women 1
• Do not continue supplementation postpartum if no risk factors for anemia are present 1
• Do not assume all prenatal vitamins contain adequate iron; verify the elemental iron content 1, 2

Side effects are dose-dependent:

• Gastrointestinal symptoms, darkening of stool/urine, and tooth staining occur more frequently with doses >60 mg daily 1
• These side effects reduce compliance, making lower prophylactic doses preferable when appropriate 2, 3