Family Nurse Practitioner Exam

What causes physiologic anemia during pregnancy?

1. An increase in the cardiac output at the end of the second trimester

2. A physiologic decrease in the production of RBCs in pregnant women

3. An increase of up to 50% of the plasma volume in pregnant women

4. An increase in the need for dietary iron in pregnancy

The correct answer is: An increase of up to 50% of the plasma volume in pregnant women

Physiologic anemia during pregnancy is primarily caused by an increase of up to 50% in plasma volume. This phenomenon is a normal adjustment in the body that allows for increased blood volume to provide adequate circulation for both the mother and the developing fetus. The expansion in plasma volume occurs significantly in the second trimester and is crucial for supporting the increased demands placed on the mother's body, including effective nutrient delivery and waste removal for both the mother and the fetus. As plasma volume increases, the concentration of red blood cells (RBCs) becomes diluted, leading to a lower hemoglobin concentration, which is often referred to as physiologic anemia. This dilutional effect can make it seem as though there is a decrease in the number of red blood cells, even though actual production might be adequate or even increased to meet the body’s needs. The other options, while related to aspects of pregnancy, do not directly cause physiologic anemia. An increase in cardiac output at the end of the second trimester is a result of the expanded blood volume but does not cause anemia itself. A decrease in RBC production is not typically seen in normal pregnancy; instead, there is an increase in production to meet the physiological demands. Lastly, while an increased need for dietary iron exists