Urinary Stress Incontinence
Female stress incontinence is a very common problem experienced by 22% of women (based on a study group of 45 year old Danish women). Women complain of urine leakage during episodes of raised intra-abdominal pressure (eg. coughing, laughing, exercise, sport). These women experience significant difficulties including:
- increased laundering and sanitary protection cost,
- lower self esteem,
- withdrawal from social activities (gym, netball, dancing, golf and tennis).
Although commonly seen in middle aged and elderly women, when a group of female student nurses who had not had children where questioned, 40% admitted some form of incontinence. Many women avoid seeking medical help due to the misconception that the condition is a normal part of ageing or due to embarrassment. In an American study by Amber Olsen over 1 in 10 American women underwent continence and/or prolapse surgery in their lifetime.
Cause of stress incontinence
The most common problem is a lack of support to the upper urethra and bladder outlet (urethral hypermobility). A second problem, seen in about 15% of women with urinary stress incontinence, is poor urethral function. This is frequently termed Intrinsic Sphincter Deficiency (ISD). The two conditions are diagnosed and differentiated on Urodynamics.
The upper urethra and bladder outlet is cradled by pelvic floor muscle and fascia (connective tissue). This tissue acts like a hammock to resist the downward pressure on the bladder and urethra during episodes of raised intrabdominal pressure. If the supporting muscle and connective tissue is firm there will be no stress incontinece. If there is a lack of support to upper urethra (urethral hypermobility) stress urinary leakage may occur.
Poor urethral function (ISD) is associated with more severe stress incontinence, continuous leakage or leakage with minimal exertion. It is seen in:
- Older women,
- Woman after having undergone multiple previous continence surgeries,
- Woman after having undergone previous radiation therapy,
- Woman after having undergone a radical hysterectomy.
Women with poor urethral function are more difficult to treat and are associated with a lower success rate than in those with normal urethral function.
Possible risk factors for stress incontinence
Urinary stress incontinence has many possible causes including:
Age: Generally believed the prevalence of incontinence increases with age but others believe stress incontinence may be most common in women in there 40’s.
Childbirth: Stress incontinence is seen more frequently in women who have had children than in those who have not. Increasing number of children and larger birth weight of children may be a risk factor.
Race: Traditionally Caucasian women are thought to be at greater risk than Asian or Negro women. This area remains unclear.
Menopause: Is not thought to be a significant risk factor for urinary stress incontinence. Some studies suggest incontinence is greater in premenopausal than in postmenopausal women.
Obesity: Is more common in incontinent women than continent women. The surgical correction of incontinence is difficult and the long-term efficacy of surgery may be reduced in obese women
Smoking: Women who smoked are 2-3 times more likely to develop stress incontinence than nonsmokers.
Hysterectomy: Although many women believe a hysterectomy may have caused their leakage there is no proof of this in the literature.
Connective tissue: Women with stress incontinence have increased number of enzymes that break down the connective tissue. The common enzymes that are increased include collagenases and elastases. They may be related to increased incidence of “stretch marks”, hernias and increased joint flexibility seen in women with pelvic floor dysfunction.
Correct reversible conditions: bladder infection, excessive fluid intake, change medications (minipress used in hypertension may cause stress incontinence), treat chest problems (coughing), constipation, obesity.
Conservative and surgical treatments are available.