Iron Supplementation During Pregnancy
All pregnant women should receive 30 mg of elemental iron daily as prophylaxis starting at the first prenatal visit, with higher doses of 60-120 mg daily for treatment of iron deficiency anemia. 1
Primary Prevention
Iron supplementation during pregnancy is essential due to the significantly increased iron requirements, particularly during the second and third trimesters when demand for absorbed iron increases from 0.8 mg/day in early pregnancy to 7.5 mg/day in late pregnancy 2.
Prophylactic Iron Supplementation
- Start oral, low-dose (30 mg/day) iron supplements at the first prenatal visit 3, 1
- Continue throughout pregnancy
- Take supplements at bedtime or between meals to optimize absorption 1
- Encourage consumption of iron-rich foods and foods that enhance iron absorption 3
Screening and Monitoring
Initial Assessment
- Screen all pregnant women for anemia at the first prenatal care visit 3, 1
- Use anemia criteria specific to the stage of pregnancy 3
Follow-up
- Confirm positive anemia screening with repeat hemoglobin/hematocrit test 3
- If hemoglobin is less than 9.0 g/dL or hematocrit is less than 27.0%, refer to a physician familiar with anemia during pregnancy 3
Treatment of Iron Deficiency Anemia
When anemia is detected during pregnancy:
- Increase iron dosage to 60-120 mg/day 3, 1
- Monitor response after 4 weeks of treatment 3
- If no response (hemoglobin increase <1 g/dL or hematocrit <3%), further evaluate using additional tests (MCV, RDW, serum ferritin) 3
- Once hemoglobin normalizes for gestational age, reduce dosage to prophylactic level (30 mg/day) 3, 1
Special Considerations
High-Risk Groups
Women with these risk factors may need closer monitoring:
- Previous iron deficiency anemia 3
- Low iron intake 3
- Vegetarian diet (may require almost twice as much iron due to lower absorption of non-heme iron) 1
- Extensive menstrual or other blood loss prior to pregnancy 3
Postpartum Period
- Screen women at risk for anemia at 4-6 weeks postpartum 3
- Risk factors include anemia continued through third trimester and excessive blood loss during delivery 3
Side Effects and Management
Common side effects of iron supplementation include:
To minimize side effects:
- Take with meals to reduce gastrointestinal discomfort 4
- Use low-dose supplementation regimens (30 mg/day) which are as effective as higher dose regimens in preventing iron deficiency anemia and reduce unwanted side effects 3
Importance of Compliance
Poor compliance is a major challenge with iron supplementation during pregnancy 5, 6. Studies show that hemoglobin levels improve significantly only among strictly compliant pregnant women, while decreasing among partially compliant and non-compliant women 5.
Safety Warning
The FDA warns that accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6. Keep supplements out of reach of children 4.
Evidence Supporting Supplementation
Research demonstrates that:
- Only 20% of fertile women have iron reserves >500 mg (the required minimum during pregnancy) 2
- 40% have virtually no iron stores 2
- Iron absorption increases during pregnancy but not enough to prevent iron deficiency anemia in 20% of women not taking supplementary iron 2
- A supplement of 40 mg ferrous iron/day from 18 weeks of gestation appears adequate to prevent iron deficiency in 90% of women and iron deficiency anemia in at least 95% of women during pregnancy and postpartum 7
Human studies have shown that iron supplementation during pregnancy not only improves maternal iron status but also benefits the infant, as children born to iron-treated mothers have higher serum ferritin levels than those born to placebo-treated mothers 2.
Human studies have shown that iron supplementation during pregnancy not only improves maternal iron status but also benefits the infant, as children born to iron-treated mothers have higher serum ferritin levels than those born to placebo-treated mothers 2.