Which of the following regarding cardiovascular changes in pregnancy is not true?
**Core Concept**
Pregnancy is associated with significant cardiovascular changes to accommodate the increased metabolic demands of the growing fetus. These changes include an increase in cardiac output, a decrease in systemic vascular resistance, and a decrease in blood pressure. The cardiovascular system undergoes these adaptations to ensure adequate oxygenation and nutrient delivery to the fetus.
**Why the Correct Answer is Right**
The cardiovascular changes in pregnancy are mediated by the increased levels of progesterone, which causes vasodilation and a decrease in systemic vascular resistance. This results in a decrease in blood pressure, typically observed as a decrease in diastolic blood pressure. The cardiac output increases by approximately 30-40% due to an increase in stroke volume and heart rate. This increase in cardiac output is necessary to meet the increased metabolic demands of the growing fetus.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the increase in cardiac output is a true cardiovascular change in pregnancy. The cardiac output increases by approximately 30-40% due to an increase in stroke volume and heart rate.
**Option B:** This option is incorrect because the decrease in blood pressure is a true cardiovascular change in pregnancy. The decrease in blood pressure is typically observed as a decrease in diastolic blood pressure.
**Option C:** This option is incorrect because the increase in cardiac output is a true cardiovascular change in pregnancy. The cardiac output increases by approximately 30-40% due to an increase in stroke volume and heart rate.
**Clinical Pearl / High-Yield Fact**
It is essential to note that the cardiovascular changes in pregnancy are subtle and may not always be detectable on physical examination. However, they are crucial for ensuring adequate oxygenation and nutrient delivery to the fetus.
**Correct Answer: A.**