Acute pyelonephritis in pregnancy most often complicates _______
**Core Concept**
Acute pyelonephritis in pregnancy is a urinary tract infection involving the renal parenchyma, often caused by an ascending infection from the lower urinary tract. The condition poses significant risks to both the mother and fetus, necessitating prompt diagnosis and treatment.
**Why the Correct Answer is Right**
The correct answer is **C. Uncomplicated urinary tract infections (UTIs) are common in pregnancy, but pyelonephritis is more likely to occur in women with pre-existing urinary tract abnormalities, such as vesicoureteral reflux, renal calculi, or neurogenic bladder.** These conditions increase the risk of pyelonephritis due to impaired urine flow and stasis, facilitating bacterial ascent. Moreover, pregnancy-related physiological changes, such as ureteral dilation and decreased bladder capacity, further elevate this risk.
**Why Each Wrong Option is Incorrect**
* **Option A:** While pregnancy does increase the risk of UTIs, it does not directly increase the risk of pyelonephritis. Pyelonephritis is more associated with pre-existing urinary tract abnormalities.
* **Option B:** This option is incorrect because pyelonephritis is more common in women with pre-existing urinary tract abnormalities, not those without any underlying conditions.
* **Option D:** This option is incorrect as pyelonephritis is not typically associated with a history of UTIs in the past; rather, it is more related to underlying urinary tract abnormalities.
**Clinical Pearl / High-Yield Fact**
Pregnant women with a history of urinary tract abnormalities or recurrent UTIs are at increased risk of pyelonephritis. Prompt evaluation and treatment of these conditions can help prevent pyelonephritis and minimize risks to the mother and fetus.
**Correct Answer:** C. Uncomplicated urinary tract infections are common in pregnancy, but pyelonephritis is more likely to occur in women with pre-existing urinary tract abnormalities.