Urogynaecology Urodynamics


What are Urodynamics?

The investigation of functional disorders of the lower urinary tract i.e. the bladder and the urethra.

Urodynamic tests help doctors assess the function of your bladder .  They are usually done to investigate urinary incontinence in women.

During the tests, your bladder is filled and then emptied while pressure readings are taken from your bladder and your tummy (abdomen).  The idea is to replicate your symptoms, then examine them and determine their cause.

What do the tests involve?


For Uroflow and CMG (cystometrogram) you require a comfortably full bladder at appointment time. The purpose of this test is to assess how much your bladder can hold and how well it empties when you pass urine.

When your bladder feels comfortably full you will be asked to pass urine into a specially designed toilet that till record your urinary flow rate.

Bladder scan

After the Uroflow test your bladder may be scanned using an ultrasound machine to see if the bladder has emptied completely or not.


This procedure known as a Cystometrogram involves  the insertion of a small, fine catheter or hollow tube into your bladder to record pressures within the bladder. Another small tube is placed in your rectum to record the intra abdominal pressure.

Your bladder is then filled with saline solution until you feel a strong urge to void. You will then be asked to empty your bladder into a specially designed toilet with the catheters still in position. These are completely removed once the test is completed.

What happens during a Urodynamic test?

For the first part of the test, you will need to empty your bladder into a special toilet called a flowmeter.  This measures how much urine you pass and the flow of the urine.  You will usually be left alone in the room whilst you are doing this.  This is why you need to come to the test with a full bladder.

The next part of the test measures the way your bladder works as it fills up.  You will be asked to lie down on a special bed.  Two very thin tubes (catheters) are put into your bladder, by inserting them into the tube from your bladder that passes out urine (your urethra).  You may find this a little uncomfortable. One is to fill up your bladder and the other to measure the pressure in your bladder.  Another catheter is put into your vagina or back passage (rectum). This allows the pressure inside your bladder to be compared with the pressure outside your bladder.

Once the catheters are in the correct position, fluid runs into your bladder at a controlled rate.  This slowly fills your bladder whilst recordings are made. The nurse performing the test will ask you questions – for example, how your bladder feels and when it feels full.

Once your bladder is full you may be asked to cough. If you leak urine when you cough, try not to feel embarrassed.  If you leak at home when you cough, it is best for the test operator to see you leak during the test.  It is important to remember that it is helpful to see how your bladder behaves on a day-to-day basis to make sure that the correct treatment is provided.

You will then be asked to empty your bladder into the special toilet again at the end of the test, with the catheters still in place.