Before birth

The 20 week antenatal ultrasound scan looks at your baby growing in the womb. It also measures the amount of amniotic fluid (or liquor), the liquid that surrounds your baby, which is partly made up of his urine. 

PUV cannot be seen in the scan. They may be suspected in a boy if there are: 

  • a swollen bladder, ureters or kidneys – this may be a sign that urine is blocked from leaving the bladder
  • a low amount of amniotic fluid (the liquid around the baby) – this may be another sign of blockage, or that the kidneys are not making as much urine as they should. 

You may need to go back to the hospital for more ultrasound scans during pregnancy. You may be referred to specialist healthcare professionals, such as a paediatric urologist (a surgeon who treats children with problems of the urinary system) or a paediatric nephrologist (a doctor who treats children with kidney problems). 

Antenatal hydronephrosis 

Antenatal hydronephrosis is a problem found in antenatal scans. One or both kidneys hold on to urine. The affected kidney becomes stretched and swollen. 

Occasionally, antenatal hydronephrosis is caused by a problem such as PUV. 

After birth

In some boys, PUV are not diagnosed until later in life. Signs of PUV include problems passing urine, wetting themselves or urinary tract infections. Your child will need some tests to find out whether he has PUV. 

Imaging tests

Imaging tests are used to help find out what is causing the problem. These use special scanners that take pictures of the inside of the body. 

  • Ultrasound scan – this is usually the first test, which looks at look at the shape and size of your child’s kidneys and other parts of his urinary system.  A small probe (like a stick or wand) with jelly on its tip is moved around your baby’s skin. A machine attached to the probe directs sound waves into his body – your child cannot feel these. These sound waves are turned into images (pictures) that can be seen on a screen.  
  • MCUG (sometimes called a VCUG) – if your doctor finds a problem on the ultrasound, this test can check how your child is passing urine. A special X-ray machine takes a series of images of the bladder while your child passes urine. 
  • A DMSA scan or a MAG3 scan may also be arranged to find out well the kidneys are working. These are normally done after a baby is 3 or more weeks old. In each test, a chemical that gives out a small amount of radiation (energy) is injected into one of your child’s blood vessels – a special gel or cream can be used to stop your child feeling any pain. A special camera takes images of your child’s urinary system as the chemical passes through it. 

Your doctor will talk to you about the tests, any risks and how to help your child prepare for them.

Blood tests

Blood tests can find out how well his kidneys are working (kidney function). A small amount of blood will be taken from a vein, with a needle and syringe. A special gel or cream can be used to help your child stop feeling any pain.

Urine tests

You, or a nurse, will need to collect some of your child’s urine in a small, clean container for a urine test. A dipstick will be dipped into the urine – this is a strip with chemical pads that change colour depending on what substances are in the urine. The sample may also be sent to a laboratory for more accurate tests.