All about stress urinary incontinence

The kidneys produce urine which passes through the ureters to enter the bladder, a hollow and distensible organ that sits on the pelvic floor that has a hammock-like structure comprising muscles and connective tissue. The pelvic floor supports organs like the bladder, intestines, and the uterus in females and has a narrow gap through which the urethra, rectum, anus, and vagina traverse.

The urine exits the bladder through the urethra. This occurs when both the bladder?s internal and external sphincters are opened. The control of the former is involuntary and the latter, which is a circular muscle around the urethra, voluntary. Although there is individual variation in bladder capacity, it is generally accepted that the capacity in the adult is about 500 ml. The desire to urinate occurs when the bladder volume is about 300 to 350 ml. As the bladder continues to fill, the desire to urinate increases and becomes more difficult to ignore.

The bladder can store a large volume of urine without much increase in internal pressure. When there is an increase in intra-abdominal pressure, e.g. coughing, sneezing, laughing, heavy lifting, exercising, or changing position, this is usually transmitted equally to the pelvic floor and organs, including the bladder.

However, when there is weakness of the pelvic floor muscles and/or external sphincter, or malfunction of the external sphincter, an involuntary leakage of urine can occur when the intra-abdominal pressure is increased. This is because the external sphincter cannot stay closed to prevent urine flow from the bladder, and this is called stress urinary incontinence (SUI).

SUI has to be distinguished from urge incontinence, which is due to overactive bladder muscles that leads to a strong urge to urinate even when there is little urine in the bladder.

There may be situations in which there is both SUI and urge incontinence. There are also other causes of incontinence like prostate problems and nerve damage.

In short, urinary incontinence is tantamount to loss of bladder control. The symptoms can range from mild leaks to uncontrollable ones. It can happen at any age but is more common with increasing age.

Irrespective of whether the amount of urine leaked is small or large, incontinence can be distressing and embarrassing.

Risk factors

Risk factors

There are several factors that increase the risk of SUI - which is the most common type of urinary incontinence in women.

Pregnancy and childbirth increase the risk of SUI. The increasing weight of the developing baby in pregnancy exerts increased stress on the pelvic floor. Furthermore, the hormone, relaxin, which is produced in pregnancy, softens the pelvic floor muscles in preparation for childbirth. These changes result in SUI in about half of all pregnant women.

During vaginal delivery, the pelvic floor can get stretched and bruised. This can have subsequent effects on the functioning of the pelvic nerves and muscles. A Danish study of more than 2,000 women reported that the risk of developing urinary incontinence was increased three times in women who had a perineal tear or episiotomy.

SUI which develops during pregnancy or after childbirth usually improves with time. However, it may recur and treatment may be required.

After the cessation of periods (menopause), oestrogen levels are decreased considerably. As the pelvic floor is oestrogen dependent, the muscle pressure around the urethra is weaker after menopause. This, combined with the decreased elasticity of the urethra with consequent inability to close completely, increase the likelihood of SUI.

Postmenopausal women are also more likely to be overweight and have had a hysterectomy, both of which increase the risk of SUI. Hysterectomy is an operation in which the uterus is removed and can lead to damage of the pelvic floor.

There is more pressure on the abdomen in the overweight, with consequent increase in pressure on the pelvic floor. A British study reported that overweight women were twice as likely to have SUI when compared to someone of normal weight.

Chronic cough, which is more common in smokers, increases the pressure on the pelvic floor, thereby weakening its muscles and increasing the risk of SUI.

Some medicines can affect the pelvic floor, e.g. some high blood pressure medicines, antidepressants, sedatives, and muscle relaxants.

The bladder's sphincter muscle can be damaged by pelvic fracture, bladder neck surgery or radical prostatectomy in men. And there are some rare individuals who have an inherited weakness of the pelvic floor muscles.

Clinical features

Clinical features

Patients with SUI complain of an involuntary loss of urine when coughing, sneezing, laughing, heavy lifting, exercising, changing position, or during sexual intercourse.

The physical examination will involve a general, abdominal and rectal examination, including a pelvic examination in women and genital examination in men.

The findings may include bulging of the bladder or urethra into the vaginal space (cystocoele or urethrocoele) and/or uterine prolapse. SUI can be tested by getting the patient to cough, strain, or stand with a full bladder.

The usual investigations include an abdominal and/or pelvic ultrasound and urinalysis and/or culture to exclude urinary tract infection.

Other investigations include checking the residual urine in the bladder after voiding and a pad test which involves weighing a pre-weighed sanitary pad after exercise to determine the amount of urine loss.

Other investigations that may be done include x-rays of the urinary tract after intravenous injection of dye, i.e. intravenous pyelogram (IVP), urodynamic studies, inspecting the inside of the bladder with a telescope-like instrument (cystoscopy), and rarely, electromyography to check on the muscle activity.

Patients may also be asked to keep a record of the times of voiding and leaking of urine.


There are four management modalities available, i.e. lifestyle changes, pelvic floor exercises, medicines, and surgery. The modalities may be used alone or in combination The choice(s) are influenced by the severity of the problem and the extent to which it interferes with daily life.

Lifestyle changes include smoking cessation; weight reduction, if overweight; good diabetic control; voiding more often to reduce the amount of urine that leaks; ensuring regular bowel movements to avoid constipation, which can worsen SUI; avoiding excessive fluid intake, caffeine and alcohol (which can stimulate the bladder), and food and drinks that may irritate the bladder, e.g. carbonated drinks; and avoiding heavy lifting, running, or jumping.

Pelvic floor muscle training (PFMT), often called Kegel exercise, strengthens the pelvic floor muscles, particularly the urethral sphincter. It involves alternate contraction and relaxation of the pelvic floor muscles. The challenge for many women is to identify the muscles. This can be done by inserting a finger into the vagina and squeezing the surrounding muscles. The vagina would tighten and the pelvic floor moves upward. Upon relaxation of the muscles, the pelvic floor would return to the starting position.

Men can also do PFMT. The pelvic floor muscles can be identified during voiding and attempting to stop it completely once urine starts to flow. The muscles that tighten up are the pelvic floor muscles.

PFMT can be done at any time without other persons noticing it. One should try and do PFMT as advised by the doctor. If done regularly, an improvement (less frequent leakage) will be noticeable within four to 12 weeks.

Helps with all types

A review of trials published in the Cochrane database found that "pelvic floor muscle training (muscle-clenching exercises) helps women with all types of incontinence, although women with stress incontinence who exercise for three months or more benefit most."

The review reported "support for the widespread recommendation that PFMT be included in first-line conservative management programmes for women with stress, urge, or mixed, urinary incontinence."

Different types of medicines may be prescribed in SUI. They include antibiotics for urinary tract infections and topical oestrogens in post-menopausal women. The latter improves urinary frequency and urgency as well as the tone and blood supply of the urethral sphincter muscles.

However, whether oestrogens improve SUI is controversial.

Surgery is recommended for SUI in selected patients, usually after PFMT has been attempted. Various surgical techniques are available. They include anterior vaginal repair; colposuspension; collagen injections; tension free vaginal tape; and vaginal sling procedures.

The gynaecologist or the urologist, who are the specialists who perform such procedures, will discuss with the patient the pros and cons of the different techniques.

There are risks of complications in surgery and they include surgical site infections, urinary tract infections, vaginal infections, erosion of the surgically placed materials, and painful sexual intercourse. Although uncommon, complications can and do occur.

Failures of treatment are more common in patients who have conditions that hamper healing or surgery, have other problems of the genitourinary tract, or whose surgery failed previously.

Performing PFMT may help prevent symptoms and doing it during and after pregnancy can decrease the risk of developing SUI after childbirth.

Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor.