Kidney Infection in Pregnancy: Complete Guide
Kidney infections are more common in pregnancy than at other times, and because they can become serious quickly, they're always treated as needing prompt medical attention rather than something to wait out at home.
Why kidney infections are more common in pregnancy
Pregnancy hormones relax the muscles of the urinary tract, and the growing womb puts pressure on the bladder and ureters (the tubes connecting the kidneys to the bladder). Together, this slows the normal flow of urine, making it easier for bacteria to travel up from the bladder to the kidneys. A kidney infection — medically called pyelonephritis — often starts as an untreated or missed urinary tract infection (UTI), which is why any UTI symptoms in pregnancy should be reported and treated promptly rather than left to settle on their own.
Signs and symptoms to watch for
A kidney infection tends to feel more severe than a simple bladder infection. Symptoms can include:
- A high temperature or fever, sometimes with shivering or chills
- Pain in your back or side, usually below the ribs, on one or both sides
- Nausea and vomiting
- Needing to urinate more often than usual
- A burning or stinging feeling when you urinate
- Feeling generally unwell, achy, or exhausted
- Cloudy, strong-smelling, or blood-stained urine
If you have any combination of these symptoms, contact your midwife, GP, or maternity unit the same day rather than waiting for a routine appointment.
How it's treated
Because kidney infections in pregnancy can progress quickly, they're usually treated more cautiously than in someone who isn't pregnant:
- Assessment is often done at the hospital maternity unit or via your GP, sometimes leading to admission for observation
- Treatment is with antibiotics, and IV (intravenous) antibiotics are commonly used initially so the medication works quickly and reliably
- You may be monitored for a period to check your temperature, hydration, and how your baby is doing
- Once you're improving, you'll usually complete a course of oral antibiotics at home
- Pain relief and fluids are also part of routine care while you recover
Left untreated, a kidney infection in pregnancy can lead to complications including premature labour and, rarely, a serious body-wide infection (sepsis) — which is exactly why doctors treat these infections urgently rather than cautiously waiting to see how symptoms develop.
Reducing your risk
You can lower your chances of developing a kidney infection by:
- Drinking plenty of water throughout the day
- Urinating when you need to rather than holding it in, and emptying your bladder fully
- Wiping front to back after using the toilet
- Getting any UTI symptoms checked and treated promptly, even if they seem mild
Frequently Asked Questions
Are kidney infections common in pregnancy?
They're more common than outside pregnancy because hormonal and physical changes slow urine flow through the urinary tract, making infection easier to develop. They usually start as an untreated UTI, which is why prompt treatment of any bladder infection symptoms matters.
Can a kidney infection harm my baby?
An untreated kidney infection can increase the risk of complications including premature labour, so it's treated as an urgent medical issue rather than something to monitor at home. With prompt antibiotic treatment, most people recover fully and go on to have a healthy pregnancy.
What should I do if I think I have a kidney infection?
Contact your GP, midwife, or maternity unit straight away — don't wait for the symptoms to pass or for a routine appointment. If it's out of hours and you have a fever with back pain, vomiting, or feel very unwell, go to your nearest A&E or contact NHS 111 for urgent advice.
This article is for informational purposes only and does not constitute medical advice.
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