From the Guidelines
Iron deficiency anemia in pregnancy should be treated with oral iron supplementation, typically ferrous sulfate 300 mg (containing 60 mg elemental iron) taken once or twice daily between meals with vitamin C to enhance absorption, as recommended by the most recent guidelines 1.
Diagnosis and Screening
For Canadian pregnant women, screening is recommended at the first prenatal visit and again at 24-28 weeks. Diagnosis is confirmed when hemoglobin is below 110 g/L in the first trimester or below 105 g/L in the second and third trimesters, along with low ferritin levels (below 30 μg/L) 1.
Treatment and Management
Treatment should continue for 3 months after hemoglobin normalizes to replenish iron stores. Common side effects include constipation, nausea, and dark stools; these can be managed by taking iron with food (though this reduces absorption) or switching to alternate formulations like ferrous gluconate.
Severe Anemia and Alternative Treatments
For severe anemia (hemoglobin below 70 g/L) or when oral therapy fails, intravenous iron (iron sucrose or ferric carboxymaltose) may be necessary, as supported by recent studies 1.
Importance of Treatment
Iron deficiency anemia requires treatment because it increases risks of preterm birth, low birth weight, and postpartum depression, while adequate iron is essential for fetal neurodevelopment and maternal wellbeing during pregnancy's increased blood volume demands, as highlighted in the guidelines 1. Some key points to consider:
- The usual dose of elemental iron per day is 60 to 120 mg 1
- Prenatal vitamins often include a low dose of iron; the usual dose prescribed in early pregnancy is 30 mg of elemental iron per day 1
- Higher doses (60 to 100 mg of elemental iron per day) are sometimes prescribed in populations at increased risk for iron deficiency anemia 1
From the Research
Iron Deficiency Anemia in Pregnancy
- Iron deficiency anemia is a common condition during pregnancy, and it can have significant effects on both the mother and the fetus 2, 3, 4.
- Daily oral iron supplementation during pregnancy has been shown to reduce the risk of maternal anemia and iron deficiency at term 2, 3, 4.
- The evidence suggests that iron supplementation may also reduce the risk of low birthweight and preterm birth, although the results are not always statistically significant 2, 3, 4.
- Women taking iron supplements are more likely to have higher hemoglobin concentrations at term and in the postpartum period, but they are also at increased risk of hemoglobin concentrations greater than 130 g/L during pregnancy and at term 2, 3, 4.
Diagnosis and Treatment
- The most efficient test for the diagnosis of iron deficiency is the serum ferritin 5.
- Iron replacement can be done orally, or in patients in whom oral iron is not effective or contraindicated, with intravenous iron 6, 5.
- Hemoglobin response at day 14 of oral iron may be useful in assessing whether and when to transition patients from oral to intravenous iron 6.
Benefits and Risks
- Iron supplementation during pregnancy may reduce maternal anemia and iron deficiency at term, and it may also improve other maternal and birth outcomes 2, 3, 4.
- However, iron supplementation can also cause side effects, such as nausea, vomiting, and diarrhea, and it may increase the risk of hemoglobin concentrations greater than 130 g/L during pregnancy and at term 2, 3, 4.
- The evidence is uncertain about the effects of iron supplementation on other maternal and infant health outcomes, including infant iron status, growth, and development 4.