Physiologic anemia often occurs during pregnancy as a result of
A.
The fetus is establishing iron stores.
B.
Inadequate intake of iron.
C.
Decreased production of erythrocytes (RBC)
D.
Dilution of hemoglobin concentration
The Correct Answer and Explanation is:
The correct answer is D. Dilution of hemoglobin concentration.
Explanation:
Physiologic anemia during pregnancy is a common and expected occurrence, primarily due to the physiological changes in the body. The condition is often referred to as “dilutional anemia” or “physiologic anemia of pregnancy.” This phenomenon occurs due to the following reasons:
- Increased Plasma Volume: During pregnancy, the blood volume increases significantly to accommodate the growing needs of the fetus and the placenta. Plasma volume expands more than the red blood cell mass. As a result, the concentration of hemoglobin and hematocrit decreases, which is termed as dilutional anemia. The red blood cell mass does increase during pregnancy, but not proportionally to the increase in plasma volume.
- Hemodilution: The term “hemodilution” describes the process whereby the increased plasma volume dilutes the concentration of red blood cells (RBCs), leading to a lower concentration of hemoglobin in the blood. This dilution effect is a normal adaptation of the body to ensure that adequate blood flow and nutrients are delivered to the fetus. Hemoglobin levels typically drop during the first and second trimesters but usually return to normal levels by the third trimester as the red blood cell mass increases to better match the expanded plasma volume.
- Iron Needs and Utilization: Although iron needs increase during pregnancy due to the demands of the developing fetus and placenta, physiologic anemia itself is primarily due to hemodilution rather than inadequate iron intake. Adequate iron intake is crucial for the production of red blood cells, but in cases of physiologic anemia, the primary issue is the dilution effect rather than a deficiency in iron stores.
- Normal Adaptation: This type of anemia is considered normal and adaptive, provided that the mother’s iron stores are sufficient and that the anemia does not become severe. It is important for healthcare providers to monitor hemoglobin levels and ensure that the mother is receiving adequate prenatal care, including appropriate iron supplementation if needed.
In summary, physiologic anemia in pregnancy is predominantly due to the dilution of hemoglobin concentration resulting from the increased plasma volume rather than inadequate iron intake or decreased production of red blood cells.