Is the management of iron deficiency anemia the same during pregnancy?

Management of Iron Deficiency Anemia During Pregnancy

The management of iron deficiency anemia during pregnancy differs significantly from non-pregnant patients, requiring universal iron supplementation and more aggressive screening due to increased iron demands and physiological changes specific to pregnancy.

Increased Iron Requirements in Pregnancy

Pregnancy creates unique physiological demands for iron that are not present in non-pregnant individuals:

• Blood volume expands by approximately 35% during pregnancy 1
• Iron demand increases threefold in the second and third trimesters to approximately 5.0 mg iron/day 1
• Iron is needed for fetal and placental development in addition to maternal needs 1
• Most pregnant women cannot maintain adequate iron stores without supplementation, particularly during second and third trimesters 1

Screening Recommendations

Screening for iron deficiency anemia during pregnancy is more intensive:

• The American College of Obstetricians and Gynecologists recommends screening with complete blood count in first trimester and again at 24-28 weeks gestation 2
• Serum ferritin is the most reliable diagnostic test for iron deficiency in pregnancy (threshold < 20-30 μg/L) 3, 4
• Hemoglobin thresholds for anemia in pregnancy are:
  • First trimester: < 11.0 g/dL
  • Second/third trimester: < 10.5-11.0 g/dL 2

Treatment Approach

Oral Iron Supplementation

• Universal iron supplementation is recommended for all pregnant women regardless of initial iron status 1
• Low-dose supplementation (30 mg elemental iron/day) is typically prescribed in early pregnancy 1
• Higher doses (60-120 mg elemental iron/day) are recommended for treatment of established iron deficiency anemia 1, 2
• New evidence suggests intermittent dosing may be as effective as daily dosing with fewer side effects 2

Intravenous Iron

Indications for IV iron in pregnancy (different from non-pregnant patients):

• Intolerance to oral iron
• Inability to absorb oral iron
• No response to oral iron therapy
• Severe anemia
• Late diagnosis requiring rapid correction 2, 4

Special Considerations

• Iron supplements should not be taken within 2 hours of tetracycline antibiotics due to absorption interference 5
• Common side effects include gastrointestinal discomfort, nausea, constipation, or diarrhea 5
• Safety closures are required for iron-containing medications due to risk of overdose in children 5

Prevalence and Risk Factors

The prevalence of anemia increases throughout pregnancy:

• First trimester: 9%
• Second trimester: 14%
• Third trimester: 37% 1

Higher risk groups include:

• Non-Hispanic Black and Mexican American women
• Women with parity of 2 or more
• Those with vegetarian diets
• Women with gastrointestinal disease or taking medications that decrease iron absorption
• Those with short intervals between pregnancies 1

Clinical Implications

Untreated iron deficiency anemia in pregnancy is associated with:

• Preterm delivery
• Low birth weight
• Maternal illness
• Intrauterine growth restriction 6
• Increased likelihood of transfusion at delivery 2

Iron deficiency anemia management during pregnancy requires a proactive approach with universal supplementation and regular screening, unlike the more reactive approach typically used in non-pregnant patients.