Stress incontinence occurs because of diminished function in the bladder control muscles that regulate the release of urine.
The bladder expands as it fills with urine, but valve-like muscles in the urethra the short tube through which urine flows to exit your body normally stay closed, or contracted, preventing urine leakage until you reach a bathroom. Your urinary sphincter, within the surrounding pelvic floor muscles, supports your bladder. When those muscles weaken, pressure can cause urine leakage as you jump or run, for instance.
Your bladder may not even feel unusually full when you have urine leakage due to stress incontinence. Anything that exerts force on the abdominal and pelvic muscles sneezing, bending over, lifting, laughing hard puts pressure on your bladder.
Your urinary sphincter and pelvic floor muscles may lose strength because of:
- Childbirth. In women, poor function of pelvic floor muscles or the sphincter may occur because of tissue or nerve damage during delivery of a child. Stress incontinence from this damage may begin soon after delivery or occur years later.
- Prostate surgery. In men, the most common factor leading to stress incontinence is the surgical removal of the prostate gland (prostatectomy) to treat prostate cancer. Because the sphincter lies directly below the prostate gland and encircles the urethra, a prostatectomy may result in a weakened sphincter.
Other factors that may worsen stress incontinence include:
- Illnesses that cause chronic coughing or sneezing
- Smoking, which can cause frequent coughing
- Excess consumption of caffeine or alcohol
- High impact activities over many years
- Hormonal deficiency