Urodynamic Testing for Incontinence

What is incontinence?

The involuntary leakage of urine is called incontinence.

What causes incontinence?

Problems in the urinary system can be caused by aging, illness, or injury. The muscles in your ureters, bladder, and urethra tend to become weaker with age. You may have more urinary infections because bladder muscles have weakened and cannot empty the bladder completely. Also, weakening in the muscles of the sphincters and the pelvis can cause incontinence because the sphincter cannot remain tight enough to hold urine in the bladder or does not have enough support from the pelvic muscles.

What should I do first?

The first step in solving a urinary problem is to talk to your doctor or nurse. He or she will ask you about your general medical history, including any major illnesses or surgeries. You should discuss the medicines you take, both prescription and nonprescription, because they might be part of the problem. You should talk about how much fluid you drink a day and whether you use alcohol or caffeine. Give as many details as you can about the problem and when it started.

A physical exam will also be performed to rule out other causes of urinary problems, such as weakening pelvic muscles.

Urodynamic Testing for Incontinence - Testing

How are the causes of incontinence diagnosed?

Urodynamics is the study of how the body stores and releases urine. Urodynamic tests help your doctor or nurse see how well your bladder and sphincter muscles work and can help explain symptoms such as:

  • incontinence
  • frequent urination
  • sudden, strong urges to urinate
  • problems starting a urine stream
  • painful urination
  • problems emptying your bladder completely
  • recurrent urinary tract infections

Most urodynamic testing focuses on the bladder's ability to empty steadily and completely. It can also show whether the bladder is having abnormal contractions that cause leakage. Your doctor will want to know whether you have difficulty starting a urine stream, how hard you have to strain to maintain it, whether the stream is interrupted, and whether any urine is left in your bladder when you are done (postvoid residual).

Urodynamic tests can range from simple observation to precise measurement using sophisticated instruments.

What types of urodynamic tests will the doctor use?

Any procedure designed to provide information about a bladder problem can be called a urodynamic test. The type of test you take depends on the type of problem you are experiencing.


A cystometrogram (CMG) measures how much your bladder can hold, how much pressure builds up inside your bladder as it stores urine, and how full it is when you feel the urge to urinate.

The doctor or nurse will use a catheter to empty your bladder completely. Then a special, smaller catheter with a pressure-measuring tube called a cystometer will be used to fill your bladder slowly with warm water. Another catheter may be placed in the rectum to record pressure there as well.

You will be asked how your bladder feels and when you feel the need to urinate. The volume of water and the bladder pressure will be recorded and involuntary bladder contractions can be identified. You may be asked to cough or strain during this procedure.


While your bladder is being filled for the CMG, it may suddenly contract and squeeze some water out without warning. The cystometer will record the pressure at the point when the leakage occurred. This reading may provide information about the kind of bladder problem you have.

You may also be asked to try to exhale while holding your nose and mouth to apply abdominal pressure to the bladder or cough or shift positions. These actions help the doctor or nurse evaluate your sphincter muscles.


After the CMG, you will be asked to empty your bladder so that the catheter can measure the pressure required to urinate. Bladder outlet obstruction can occur with a fallen bladder or, in rare cases, after a surgical procedure for urinary incontinence.

When will I know the results?

Results for simple tests can be discussed with your doctor or nurse immediately after the test, while results of other tests may take a few days. You will have the chance to ask questions about the results and possible treatments for your problem.

What happens after the testing?

You may have mild discomfort for a few hours after these tests. Drinking two 8-ounce glasses of water each hour for two hours should help. Ask your doctor whether you can take a warm bath. If not, you may be able to hold a warm, damp washcloth over the urethral opening to relieve the discomfort.

Your doctor may give you an antibiotic to take for one or two days to prevent an infection. If you have signs of infection—including pain, chills, or fever—call your doctor at once.


United States National Institute of Diabetes & Digestive & Kidney Diseases, of the National Institutes of Health: http://kidney.niddk.nih.gov/kudiseases/pubs/urodynamic/index.htm