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Pyelonephritis in pregnancy

It can cause premature births and hospitalisation during pregnancy so it’s definitely worth knowing about a type of urinary tract infection called pyelonephritis

Urinary tract infections (UTIs) are more common during pregnancy. This is mostly because there are a whole load of changes going on around there at this time.

Pyelonephritis is one of the most serious types of UTIs and one of the ones most likely to get you admitted to hospital. As well as affecting the upper urinary tract, pyelonephritis affects the kidneys (Goumi et al, 2015).

Pyelonephritis usually happens if you’ve had cystitis (a lower urinary tract infection) and the bacteria then travels up into the kidneys (Goumi et al, 2015; NHS Choices, 2018).

Pyelonephritis symptoms

Symptoms of pyelonephritis usually start within a few hours (NHS Choices, 2018). Some of the symptoms in pregnancy are:

  • fever
  • pain and discomfort on back or side
  • nausea
  • vomiting
  • pain in your side
  • painful, frequent or an urgent need to wee.

(Goumi et al, 2015; NHS Choices, 2018).

Pyelonephritis causes

E.coli bacteria is the usual cause of pyelonephritis. This bacteria causes pyelonephritis by travelling up to the bladder, causing cystitis, then continuing up into the kidneys. Both of which are the last things you need when you’re pregnant.

E. coli normally live in the bowel where they cause no harm. But they can be transferred into the vagina during sex or when you wipe after you go to the toilet (NHS Choices, 2018). And that’s when you have a problem.

Pyelonephritis is more common in women as their urethras are shorter, so it’s easier for bacteria to reach the kidneys. It’s also more likely in younger women who are sexually active as frequent sex increases the chances of a kidney infection (NHS Choices, 2018).

The best way to avoid pyelonephritis is to:

  • drink plenty of fluids
  • go to the loo as soon as you need it
  • go to the loo after sex
  • wipe from front to back after going to the loo
  • wash down below every day, and if possible before having sex
  • treat any constipation as this can increase your risk of pyelonephritis.

(NHS Choices, 2018)

When to see your GP

Pregnancy isn’t a time to be taking health risks so see your GP if:

  • you feel feverish
  • you have pain in your back, tummy or down below that won’t go away
  • your symptoms haven’t improved after a few days
  • you have blood in your wee.

(NHS Choices, 2018).

Pyelonephritis diagnosis

When they’re diagnosing pyelonephritis, your GP will ask:

  • if you have had a kidney infection before
  • what symptoms you’ve been having
  • for a urine sample.

(NHS Choices, 2018)

Will this UTI affect my baby?

If you have pyelonephritis in pregnancy, you are more likely to have your baby prematurely or to have a low birthweight baby (Goumi et al, 2015).

You’re also more likely to have complications in your kidneys (NICE, 2013). The risks are higher if you don’t have any symptoms (Goumi et al, 2015).

Pyelonephritis treatment and antibiotics in pregnancy

Pyelonephritis needs quick treatment with antibiotics to stop it from damaging the kidney or spreading to the bloodstream (NHS Choices, 2018).

If you’re pregnant and have pyelonephritis, you’ll more than likely be admitted to hospital so doctors can take regular urine and blood samples. Your doctor can speak to you about which antibiotics are safe in pregnancy and you’ll probably be given them intravenously (NICE, 2013).

This page was last reviewed in February 2018.

Further information

Our support line offers practical and emotional support with feeding your baby and general enquiries for parents, members and volunteers: 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.

You might find attending one of our NCT New Baby groups helpful as they give you the opportunity to explore different approaches to important parenting issues with a qualified group leader and other new parents in your area.

Make friends with other parents-to-be and new parents in your local area for support and friendship by seeing what NCT activities are happening nearby.

Goumi H, Goto Y, Laopaiboon M, Usui R, Mori R. (2015) Routine blood cultures in the management of pyelonepthritis in pregnancy for improving outcomes. Cochrane Database Systematic Review. (2):CD009216 Available from: [Accessed 1st February 2018]

NHS Choices. (2018) Kidney infection. Available from: [Accessed 1st February 2018]

NICE (The National Institute for Health and Care Excellence). (2013) Clinical Knowledge Summaries. Pyelonephritis – acute. Available from:!scenario [Accessed 1st February 2018]

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