**Question:** All of the following are physiological changes which occur during pregnancy, EXCEPT:

A. Increased heart rate
B. Decreased respiratory rate
C. Increased glomerular filtration rate
D. Decreased urinary output

**Core Concept:** During pregnancy, several physiological changes occur to accommodate the growing fetus and support maternal health. These changes include:

1. Increased heart rate: This helps to meet the increased cardiac output required to supply the growing fetus with oxygen and nutrients.
2. Decreased respiratory rate: Although respiratory rate may decrease, it is not a universal change; some women may experience an increase in respiratory rate due to hormonal effects.
3. Increased glomerular filtration rate: This compensates for the increased blood volume and helps maintain stable blood pressure and fluid balance.
4. Decreased urinary output: This is a compensatory mechanism to prevent excessive fluid loss and maintain blood volume stability.

**Why the Correct Answer is Right:** Decreased urinary output is a common physiological response during pregnancy. However, option D (decreased urinary output) is correct because it is an example of how the body adapts to maintain fluid balance and blood volume in pregnancy.

**Why Each Wrong Option is Incorrect:**

A. Increased heart rate is actually a compensatory mechanism to increase cardiac output and meet the increased oxygen and nutrient demand of the growing fetus.
B. While some women might experience a decrease in respiratory rate, it is not a universal change. This makes option B incorrect as it does not accurately represent the typical physiological response to pregnancy.
C. Increased glomerular filtration rate helps maintain blood pressure and fluid balance, making it an incorrect option.

**Clinical Pearl:** Understanding the various physiological changes in pregnancy is essential for healthcare professionals to provide appropriate care for pregnant patients. These changes are crucial for maintaining maternal and fetal well-being throughout the pregnancy and postpartum period.