The causes of the most common types of urinary incontinence are:

• Stress incontinence. Stress incontinence is caused by stretched pelvic floor muscles, as from childbirth or weight gain. When these muscles no longer support your bladder properly, the bladder drops downward and pushes against the vagina, preventing tightening of the muscles that ordinarily close off the urethra. Leakage can then occur when extra pressure is exerted with coughing, sneezing, laughing, or other activities. Stress incontinence may get worse with the drop in estrogen that comes after menopause. A chronic cough from smoking can also make stress incontinence worse.
• Urge incontinence. Urge incontinence results when the bladder muscle involuntarily contracts. Urge incontinence can be caused by:
  • Age-related changes in the bladder muscle.
  • Parkinson's disease.
  • Stroke.
  • Kidney or bladder stones.
  • Tumors that put pressure on the bladder, such as pelvic, cervical, or uterine cancer.
  • Tumors that irritate the lining of the bladder (bladder cancer).

Overactive bladder is a kind of urge incontinence. But not everyone with overactive bladder leaks urine. For more information, see the topic Overactive Bladder.

It is common for a woman to have mixed incontinence, usually a combination of stress incontinence and urge incontinence.

Less common types of urinary incontinence have other causes. These types include:

• Overflow incontinence. Overflow incontinence is the involuntary release of urine when the bladder becomes overly full due to a blockage, but you feel no urge to urinate. This is uncommon in women.
• Total incontinence. Total incontinence is the continuous and total loss of urinary control. There can be many causes for total incontinence, including neurogenic bladder, an involuntary contraction of the bladder that forces the release of urine, as well as spinal cord injuries, multiple sclerosis, and other disorders that affect nerve function.
• Functional incontinence. Functional incontinence occurs when a disability, such as dementia or arthritis, makes it difficult for you to reach or use a bathroom in time to urinate.
• Anatomical incontinence. Anatomical incontinence is the involuntary release of urine related to structural problems of the urinary tract that affect the urine flow. Anatomical incontinence may be present from birth (congenital).