Pyelonephritis in pregnancy is best described as infection of which organ?

• A. Kidney
• B. Bladder
• C. Ureter
• D. Adrenal gland

Answer: (A)

Pyelonephritis is an infection of the kidney, affecting the kidney tissue and the renal pelvis. The term itself refers to the upper urinary tract, where infection ascends from the bladder up into the kidney. In pregnancy, this distinction matters because the kidneys are the site of infection, not the bladder or other organs. A bladder infection would be cystitis, while infection of the ureter is not what pyelonephritis describes, and the adrenal gland is unrelated to urinary tract infections. In pregnancy, pyelonephritis can be more dangerous due to physiologic changes that promote urinary stasis and ascent of bacteria, so recognizing it as a kidney infection helps guide appropriate management.