A 17 year old primigravida asks you what to expect during her pregnancy. You tell her that normally during pregnancy:
**Core Concept**
During pregnancy, the body undergoes various physiological changes to accommodate the growing fetus. One of these changes involves the cardiovascular system, where the mother's blood volume increases significantly to meet the increased metabolic demands of the fetus.
**Why the Correct Answer is Right**
The correct answer is related to the increased blood volume during pregnancy. This increase in blood volume is a result of the body's attempt to meet the increased oxygen and nutrient demands of the fetus. The increased blood volume also helps to prepare the mother's body for the potential blood loss during delivery. This increase in blood volume is a normal physiological adaptation during pregnancy and is not a pathological condition.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the normal increase in blood pressure during pregnancy is a compensatory mechanism to maintain blood flow to the fetus and mother. However, hypertension in pregnancy can be a sign of a pathological condition.
**Option B:** This option is incorrect because the normal increase in cardiac output during pregnancy is a result of the increased blood volume and stroke volume, not a decrease.
**Option C:** This option is incorrect because the normal increase in blood volume during pregnancy is not due to fluid retention, but rather an increase in plasma volume.
**Clinical Pearl / High-Yield Fact**
It's essential to note that while an increase in blood volume is a normal physiological adaptation during pregnancy, any significant changes in blood pressure or cardiac output should be monitored closely to prevent potential complications.
**Correct Answer:** B.