Pregnancy tip

The symptoms of pyelonephritis usually develop over just a few hours.

Kidney infection in pregnancy

Being pregnant makes you more likely to develop a urinary tract infection. Sometimes a urinary tract infection reaches the kidneys (pyelonephritis) and should be treated promptly.

Pyelonephritis is an infection which has travelled up the urinary tract and has reached the kidney. The symptoms of pyelonephritis usually develop over just a few hours, and they can come on very suddenly.

Symptoms of kidney infection

Symptoms of pyelonephritis may include:

  • pain in the lower side of your back, on either side or both sides
  • fever
  • shivering
  • feeling sick
  • vomiting
  • diarrhoea
  • blood in your urine
  • your urine turning cloudy and smelling unusually bad
  • pain when you pass urine
  • needing to go to the toilet more often than normal.

Pyelonephritis is usually treated with antibiotics to clear the infection. It may require admission to hospital. 

If you are worried about any of these symptoms, see your midwife or GP or contact NHS Direct: 0845 4647.

Page last reviewed: 20 February 2012

Further information

NCT's helpline offers practical and emotional support in all areas of pregnancy, birth and early parenthood: 0300 330 0700. We also offer antenatal courses  which are a great way to find out more about birth, labour and life with a new baby.

NHS Choices has information on kidney infection