Common risk factors in the development of hydronephrosis include renal calculi, external compression from abdominal and pelvic masses and tumors such as prostate enlargement and cancer, cervical cancer, diabetes mellitus and neurogenic bladder, congenital anomalies of the kidney and urinary tract (CAKUT) such as vesicoureteric reflux, ureteropelvic junction obstruction and posterior urethral valves.

Common risk factors in the development of hydronephrosis include:^{[1][2][3][4][5][6]}

• Renal calculi, kidney stones, ureteral stones, and bladder stones
• Prostate enlargement and prostate cancer
• Pelvic and retroperitoneal masses and tumors compressing renal structures (eg, ovarian cysts, tuboovarian abscess, pelvic prolapse, retroperitoneal fibrosis, endometriosis and abdominal malignancies)
• Pregnancy
• Trauma
• Pelvic radiation
• Strictures
• Neurogenic bladder
• Urinary tract infection
• Congenital anomalies of the kidney and urinary tract that can lead to hydronephrosis include
  • Vesicourethral reflux
  • Ureteropelvic junction obstruction
  • Posterior urethral valves
  • Prune belly syndrome
  • Primary bladder neck obstruction