The symptoms of hydronephrosis may include:

• pain in the lower back, side or tummy (abdomen)
• needing to pee more often than usual
• difficulty peeing
• pee that looks cloudy
• blood in your pee
• a high temperature, or feeling hot, cold or shivery

Hydronephrosis is also common in unborn babies, which is known as antenatal hydronephrosis.

Antenatal hydronephrosis does not usually cause any symptoms in the mother or baby during pregnancy.

Ask for an urgent GP appointment or get help from NHS 111 if:

If a GP thinks you could have hydronephrosis, they may need to do some tests to find out what might be causing the symptoms. For example:

• blood or pee tests to check for infections, such as a urinary tract infection (UTI)
• a rectal examination, to check for an enlarged prostate
• an X-ray, CT scan or other tests that take pictures of your body to check for a blockage around your kidneys, bladder and the tubes that carry pee out of your body (ureters)

If your unborn baby has hydronephrosis, it's usually found during your 20-week scan.

Hydronephrosis is usually caused by something blocking the flow of pee around your kidneys and bladder and the tubes that carry pee out of your kidneys (ureters).

Some of the things that can cause a blockage include:

• kidney stones
• pregnancy
• an enlarged prostate
• infections, such as a urinary tract infection (UTI)
• an injury or surgery that damages your ureters
• a blood clot
• a tumour or some types of cancer

Antenatal hydronephrosis is usually caused by your baby producing more urine in the later stages of pregnancy. This usually goes away on its own. In more severe cases it may be caused by a blockage and may need treatment.

Treatment for hydronephrosis depends on what's causing it and how severe it is.

In adults, the first treatment is usually to drain the pee to help relieve pain and prevent damage to your kidneys.

This is done by putting a thin tube (catheter) into your bladder, through either:

• your urethra (tube that carries urine out of your body)
• a small cut in your tummy (abdomen)

Once the pee is drained, the cause can be treated. For example, you might need medicine to treat infection or surgery to remove a blockage.

Antenatal hydronephrosis does not usually need any treatment. It often gets better on its own, either during the pregnancy or after your baby is born.

If it does not get better on its own, babies and young children may be given antibiotics to prevent infection. They do not usually need other treatments.

If hydronephrosis is treated promptly, it does not usually cause any long-term problems. Most people are able to recover quickly.

However, if your hydronephrosis is not treated or is severe, it can damage your kidneys and may eventually cause kidney failure.

If this happens, you may need treatments such as dialysis or a kidney transplant.

Further information

• Antenatal hydronephrosis - InfoKID