From the Guidelines
Iron deficiency anemia and physiologic anemia of pregnancy are two distinct conditions that require different management approaches, with iron deficiency anemia necessitating treatment with oral iron supplements to prevent adverse maternal and fetal outcomes. The key difference between the two conditions lies in their cause and severity, with physiologic anemia of pregnancy being a normal adaptation to pregnancy characterized by a dilutional effect due to increased plasma volume, whereas iron deficiency anemia is a pathological state caused by inadequate iron stores 1.
Key Characteristics of Each Condition
- Physiologic anemia of pregnancy:
- Normal adaptation to pregnancy
- Plasma volume increases more than red blood cell mass
- Hemoglobin concentration typically lowers to 10.5-11 g/dL
- No treatment needed, resolves after delivery
- Iron deficiency anemia:
- True pathological state caused by inadequate iron stores
- Hemoglobin typically below 10.5 g/dL
- Requires treatment with oral iron supplements, usually 60-120 mg of elemental iron daily
- Can lead to preterm birth, low birth weight, and maternal fatigue if untreated
Management and Treatment
Treatment of iron deficiency anemia with oral iron supplements is crucial to prevent adverse outcomes, with ferrous sulfate 325 mg (containing 65 mg elemental iron) taken once or twice daily being a commonly prescribed regimen 1. It is essential to take iron supplements with vitamin C to enhance absorption and manage side effects like constipation and nausea by taking iron with food or switching to alternative formulations like ferrous gluconate.
Laboratory Findings
Laboratory findings also differ between the two conditions, with iron deficiency anemia characterized by low ferritin, low serum iron, and high total iron binding capacity, whereas these parameters remain normal in physiologic anemia 1.
Importance of Screening and Prevention
Screening for iron deficiency anemia in pregnant women is crucial, especially in high-risk populations such as non-Hispanic black and Mexican American women, and those with a diet lacking in iron-rich foods or gastrointestinal disease 1. Universal iron supplementation for pregnant women is advocated due to the potential benefits in reducing adverse birth outcomes and the low risk of adverse effects associated with supplementation 1.
From the Research
Comparison of Iron Deficiency Anemia and Physiologic Anemia of Pregnancy
- Iron deficiency anemia is a condition where the body does not have enough iron to produce adequate amounts of hemoglobin, a protein in red blood cells that carries oxygen to different parts of the body 2, 3, 4.
- Physiologic anemia of pregnancy, on the other hand, occurs due to the increase in plasma volume during pregnancy, which exceeds the increase in red cell mass, resulting in a dilutional anemia 5.
Causes and Risk Factors
- Iron deficiency anemia is mainly caused by nutritional deficiencies, parasitic and bacterial diseases, and inborn red blood cell disorders such as thalassemias 4.
- Physiologic anemia of pregnancy is a normal adaptation to pregnancy, but it can be exacerbated by factors such as uterine or placental bleeding, gastrointestinal bleeding, and peripartum blood loss 5.
Diagnosis and Treatment
- Iron deficiency anemia can be diagnosed with a complete blood count and serum ferritin levels, and treated with oral iron supplementation or intravenous iron preparations 2, 3, 4.
- Physiologic anemia of pregnancy does not require treatment, but iron supplementation may be recommended to prevent iron deficiency anemia 5.
Consequences
- Iron deficiency anemia is associated with increased maternal and perinatal morbidity and mortality, as well as neurocognitive deficits in infants 6.
- Physiologic anemia of pregnancy is generally not associated with adverse outcomes, but it can increase the risk of peripartum blood transfusion 5.
Key Differences
- Iron deficiency anemia is a pathologic condition that requires treatment, while physiologic anemia of pregnancy is a normal adaptation to pregnancy 2, 5.
- Iron deficiency anemia is associated with more severe consequences, such as increased maternal and perinatal morbidity and mortality, compared to physiologic anemia of pregnancy 6.