NICE recommends that women with urinary incontinence be categorised according to their symptoms into three groups: stress, mixed or urge urinary incontinence. Overall, approximately one-half of all women with urinary incontinence complain of pure stress incontinence and 30–40% have mixed symptoms of stress and urge incontinence. Women with mixed urinary incontinence, who have involuntary leakage associated with urgency and also with exertion, should have initial treatment targeted to the symptom that they report to be the most troublesome.

Stress incontinence is the complaint of involuntary leakage on effort or exertion, or on sneezing or coughing, and suggests a problem with urethral competence. Urodynamic stress incontinence may be noted during filling cystometry and is defined as the involuntary leakage of urine during increased abdominal pressure, in the absence of a detrusor contraction. Prevalence figures for urinary incontinence vary widely. It is thought that urinary loss secondary to urodynamic stress incontinence is slightly more common than that secondary to detrusor overactivity. These two conditions account for the vast majority of female incontinence in the developed world, although globally fistulae from obstructed labour is another major cause.

Aetiology

The aetiology of stress incontinence is undoubtedly multifactorial. Some women appear to have a congenital predisposition, possibly because of inherently weak collagenous connective tissue. Childbirth has always been known to be a major contributory factor, although robust clinical data confirming this is remarkably sparse. Other contributory factors such as the menopause are more contentious. Anything that places chronic strain on the pelvic floor may also predispose to urinary stress incontinence; such factors include constipation, obesity and chronic cough.