The causes of urinary retention are related to either a blockage that partially or fully prevents urine from leaving your bladder or urethra, or your bladder not being able to maintain a strong enough force to expel all the urine.
Blockage or narrowing in the urethra or bladder neck
For you to be able to urinate normally, all parts of your urinary tract need to work together in the correct order. Urine normally flows from your kidneys, through the ureters to your bladder, and out the urethra. If a blockage or narrowing occurs somewhere along the urinary tract, you may have difficulty urinating, and if the blockage is severe, you may not be able to urinate at all.
Medical problems that may narrow the urethra and block urine flow include
- enlarged prostate, or benign prostatic hyperplasia
- bladder outlet obstruction, such as urethral stricture or scar tissue in the bladder neck
- pelvic organ prolapse, including cystocele and rectocele
- urinary tract stones, also called calculi
- constipation
- pelvic masses, such as noncancerous or cancerous tumors, fibroids, polyps, or clots
- tight pelvic floor muscles
- infections, such as urinary tract infection, sexually transmitted diseases, or prostatitis
- trauma to the pelvis, urethra, or penis
Inefficient bladder contraction (underactive bladder)
You may develop urinary retention when your bladder muscles aren’t able to contract with enough strength or do not contract long enough to empty your bladder completely—also called underactive bladder. Causes of underactive bladder include
Neurological problems. Urinary retention can occur when there is a problem with your nervous system that prevents messages from travelling from your brain to your bladder and urethra. There are many different causes of neurological problems, including
- Parkinson’s disease
- multiple sclerosis
- Alzheimer’s disease
- stroke
- birth defects, such as spina bifida
- diabetes
- spinal cord injury
- traumatic brain injury
- pelvic injury
- vaginal birth
- Guillain-Barré syndrome
- Fowler’s syndrome
- heavy metal poisoning
Medicines. Urinary retention can be caused by certain medicines that interfere with nerve signals to your bladder, urethra, or prostate. Examples of these medicines include
- alpha-adrenergic agonists
- anticholinergics and antispasmodics
- antidepressants
- antihistamines and decongestants
- antiparkinsonian medications
- antipsychotics
- benzodiazepines
- calcium channel blockers
- nonsteroidal anti-inflammatory drugs, such as aspirin and ibuprofen
- opioids
- serotonin and noradrenaline reuptake inhibitors
Surgery. It is common to develop temporary urinary retention right after surgery. During surgery, you are often given intravenous (IV) fluid, which may lead to a full bladder. You are also given anesthesia, which can prevent you from feeling the need to urinate despite having a full bladder. In addition, pelvic surgery can cause swelling, scar tissue, and trauma that can partially or fully block the flow of urine out of your bladder or urethra.
Weak bladder muscles. Bladder muscles that are weak may not contract with enough strength or force to empty the bladder completely. Causes of weakness can include
- age-related loss of bladder muscle strength
- overdistention—a bladder that has been stretched such that the muscles are damaged
- pregnancy and childbirth
- trauma