Stress Incontinence is the symptom of loss of urine when pressure within the abdomen increases. Stress incontinence is usually described as the involuntary loss of urine while coughing, sneezing, laughing, or lifting heavy objects. Poor bladder support by the pelvic muscles results in the opening and descent of the urethra when abdominal pressure is increased. Types I, IIa, and IIb incontinence are progressive forms of this urethral "hypermobility." Childbearing predisposes some women to this type of incontinence. Intrinsic sphincter deficiency (Type III incontinence) is another cause of stress incontinence due to a nonfunctional proximal urethra that remains open at all times. It may be caused by prior surgery or by changes in the urethral tissues from aging.

Urge incontinence involves the sudden sensation of a need to urinate with inability to get to a toilet before involuntary leakage occurs. At times, urine may leak without any warning. This condition is due to an overactive bladder that suddenly contracts without the patient's desire for it to do so. It often is the result of damage to the nerve passages that connect the bladder to the brain. Causes of urge incontinence include bladder infections that irritate the bladder lining, as well as neurologic problems that affect bladder function, such as a stroke, dementia, and multiple sclerosis. In some patients, the cause remains unclear.

Mixed incontinence is a combination of both stress and urge incontinence, causing symptoms of both.

Overflow incontinence occurs when the bladder is so full that it leaks urine, or "overflows." This can happen when a blocked urethra prevents the bladder from emptying normally, such as in enlargement of the prostate. Overflow incontinence can also happen in situations where is bladder is too weak to contract and force the urine out, such as in diabetes or certain neurologic disorders.

Environmental incontinence occurs when a person is unable to get to a toilet on time. The urinary system may work well, but physical or mental disabilities or other circumstances prevent normal toilet usage.