Urinary retention is most common among men. This is due to the fact that an enlarged prostate can cause an obstruction that restricts the flow of urine and thereby prevents the bladder from emptying completely. In women, weakened, stretched or damaged supporting tissue can cause the bladder to prolapse (cystocele) and move out of position. Severe bladder prolapse can cause a blockage in the urinary tract. During childbirth, there is a temporary risk of urinary retention. This is why the midwife will ensure the bladder empties regularly to avoid problems.
Many older people suffer from weak bladder muscles. This makes urination difficult and they are unable to properly empty their bladder. Residual urine levels of less than 100 ml are usually acceptable in people older than 65 – for a younger person, these levels are abnormal.
Bladder emptying difficulties can also be caused by bladder stones or kidney stones getting stuck in the urethra or bladder, which blocks the flow of urine. The migration of these stones usually leads to pain in the lower abdomen and the kidneys and can, therefore, be quickly diagnosed. A blockage can also be linked to the narrowing of the urethra (urethral stricture), which can be congenital or caused by the frequent use of a catheter.