**Question:** The following changes occur in urinary system in pregnancy except

A. Increased urine production
B. Decreased urine concentration
C. Increased urine volume
D. Enlarged kidneys

**Core Concept:** Changes in the urinary system during pregnancy

**Why the Correct Answer is Right:**
The correct answer is **D. Enlarged kidneys** because, while other options are common physiological adaptations in pregnancy, the kidneys do not enlarge significantly. Kidney enlargement may be due to hormonal changes but is not a typical outcome of this process.

**Why Each Wrong Option is Incorrect:**

A. **Increased urine production:** This is a correct response as the increased blood volume and renal blood flow in pregnancy lead to an increased glomerular filtration rate, resulting in increased urine production.

B. **Decreased urine concentration:** This is also correct as the increased blood volume and plasma volume lead to a decreased solute concentration in the blood, making urine less concentrated.

C. **Increased urine volume:** This is accurate since the urine output increases due to the above factors and other physiological adaptations during pregnancy.

**Why the Correct Answer is Right:**

The correct answer **D. Enlarged kidneys** is wrong because the kidneys do not undergo significant enlargement during pregnancy. Kidney enlargement might occur due to hormonal changes, but this is not the typical outcome of these physiological modifications.

**Why Each Wrong Option is Incorrect:**

A. **Increased urine production:** This is correct as the elevated blood volume and renal blood flow during pregnancy lead to an increased glomerular filtration rate, resulting in increased urine output.

B. **Decreased urine concentration:** This is accurate because of the increased blood volume and plasma volume that leads to reduced solute concentration in the blood, making urine less concentrated.

C. **Increased urine volume:** This is true as the urine output increases due to the above factors and other physiological adaptations during pregnancy.

**Clinical Pearls:**

1. **Hydronephrosis:** In rare cases, a pregnant woman may develop hydronephrosis (enlarged kidneys) due to hormonal changes, but this is not the typical outcome of the physiological adjustments during pregnancy.

2. **Hematuria and proteinuria:** Increased urine volume and altered glomerular filtration rate can lead to hematuria (blood in urine) and proteinuria (protein in urine), which are common in pregnancy but not specifically related to kidney enlargement.

3. **Pyelonephritis:** Though pregnancy increases the risk of urinary tract infections, pyelonephritis (infection of the kidney) is not directly related to kidney enlargement but rather to increased susceptibility due to physiological changes in the urinary tract.

4. **Ascites:** Ascites (fluid accumulation in the abdominal cavity) is a result of increased intra-abdominal pressure and fluid shifts during pregnancy, not directly related to kidney enlargement.

In summary, while the urinary system undergoes several physiological changes during pregnancy, increased kidney size is not one of these changes. Instead, the kidneys