Urinary tract infection (UTI)

Urinary tract infections (UTIs), also known as cystitis or a bladder infection, can affect any part of your urinary system – kidneys, ureters, bladder and urethra.

Key points 

  1. About 1 in every 2 women will have at least one UTI in their lifetime. The most common is cystitis, an infection that affects your bladder.
  2. Symptoms of a UTI include burning or pain when peeing and needing to pee more often and more urgently.
  3. Antibiotics are usually used to clear the infection.
  4. Self-care includes taking pain relief and drinking plenty of water. There is no strong evidence that cranberry products help.
  5. In rare cases, the infection can spread to your kidneys. This is known as pyelonephritis and needs urgent medical care.

What is a UTI?

A UTI is an infection in some part of your urinary system. Your urinary system includes all the organs involved in making and releasing urine: 

  • Kidneys – these filter your blood to remove waste and extra water to make urine.
  • Ureter – two thin tubes of muscle, one on each side of your bladder, through which urine flows from your kidneys to your bladder.
  • Bladder – where you stores urine until you need to pee.
  • Urethra – when you pee, urine passes along your urethra, a central tube that carries urine out of your body. 

What causes a UTI?

An infection in your urinary system may be caused by: 

  • bacteria from your anal area entering your bladder via the urethra – the urethra is shorter in women than in men so it is easier for bacteria to reach the bladder and cause infection
  • bacteria introduced when the urethra is pushed on during vaginal sex
  • problems in the structure of your kidneys, bladder or tubes
  • irritation of the urethra by chemicals (eg, soaps, perfumes, vaginal hygiene sprays)
  • ulcers or inflammation near the urethra
  • sexually transmitted infection (STI), eg ,chlamydia.


Who is at risk of developing a UTI?

UTIs can occur at any age and are more common if you:

  • are female (4 times more common than in men) 
  • are pregnant (read more about UTI in pregnancy)
  • are sexually active
  • have unprotected anal sex
  • use spermicide with contraception
  • are a women who has been through menopause – the changes in the tissues of the vagina and urethra after menopause make it harder for them to defend against infection
  • have diabetes
  • have a catheter in your bladder.
  • have abnormalities in your kidneys, bladder or urinary system
  • have an immune system that is not working well (eg, due to HIV/AIDS or medication that suppresses the immune system). 

What are the symptoms of a UTI? 

Typical symptoms of a urinary tract infection include:

  • pain or burning during or immediately after peeing
  • fever, tiredness or shakiness
  • an urge to pee more often
  • passing small amounts of pee more frequently
  • pressure in your lower belly
  • urine that smells bad or looks cloudy or reddish
  • repeatedly getting out of bed to pee at night.

Fever, pain or ache in your centre back or shaking may indicate that the infection has gone to your kidneys (pyelonephritis). If this happens, see your doctor urgently.

Recognising UTI symptoms in children

Older children with UTIs can describe pain felt when peeing. Younger children may not be able to do this. Watch for other symptoms, such as fever, tiredness, feeding difficulties, loss of appetite, nausea and vomiting, tummy pain, waking at night, bed wetting or loss of bladder control during the daytime.

How is a UTI diagnosed?

See your doctor if:

  • you're a man with symptoms of a UTI
  • you're pregnant and have symptoms of a UTI
  • your child has symptoms of a UTI
  • you're caring for someone elderly who may have a UTI
  • you have not had a UTI before
  • you have blood in your pee
  • your symptoms do not improve within a few days
  • your symptoms come back after treatment.

Your doctor will ask about your symptoms and do a urine test. The urine is tested in the clinic for signs of infection. UTIs in men are unusual and usually need more tests. See urinary problems in men.

Fever, pain or ache in your centre back or shaking may indicate that the infection has gone to your kidneys (pyelonephritis). If this happens, see your doctor urgently. 

How is a UTI treated?

Pain relief only

Allowing your immune system to fight the infection (by taking only pain relief and not using antibiotics) is not recommended in New Zealand health guidelines. 

The results of two recent large randomised trials found that antibiotics reduce how long you have symptoms on average by around 2 days, and reduce the risk of pyelonephritis. However, around half to two-thirds of women who do decide to just use non-steroidal anti-inflammatories (NSAIDs) for pain relief do not end up needing antibiotics. Therefore, this is a decision to make in conjunction with your doctor. 


Antibiotics are recommended for most cases of UTIs.

Usually, a 3 to 5 day course of antibiotics is needed to treat the infection and reduce the risk of it spreading to your kidneys and causing pyelonephritis. Your symptoms should begin to improve within the first 2 days of antibiotics.

You must finish all the antibiotics to get rid of the bacteria. Stopping antibiotics early could cause the infection to return. If your symptoms continue for more than 2 days after starting treatment, or you get worse, see your doctor as soon as possible. 

If you have recurrent UTIs, or are at higher risk of complications. A repeat urine test and culture may be organised a few weeks after treatment to ensure the infection has gone. Your doctor or nurse will advise what is needed for you.

Can I get antibiotics for a UTI from my pharmacy without a prescription?

Many pharmacists are now able to sell an antibiotic called trimethoprim for the treatment of UTIs. This is available without a prescription to women aged between 16 to 65 years, who are not pregnant and do not have any other complicating factors.

Self-care when you have a UTI

  • Take paracetamol or ibuprofen for pain.
  • Drink plenty of water to avoid dehydration and help flush out the bacteria.
  • No evidence has been found for taking products that alkalise your urine (such as Ural®).
  • Cranberry juice is not a recommended treatment as there have been no randomised controlled trials to demonstrate its effectiveness.

Tips to prevent UTIs


  • Do wipe from front to back when you go to the toilet.
  • Do try to fully empty your bladder when you pee.
  • Do drink plenty of fluids.
  • Do take showers instead of baths.
  • Do wear loose cotton underwear.
  • Do pee as soon as possible after sex.
  • Do change your baby's or toddler's nappies regularly.


  • Don't use perfumed bubble bath, soap or talcum powder.
  • Don't hold your pee in if you feel the urge to go.
  • Don't wear tight, synthetic underwear, such as nylon.
  • Don't wear tight jeans or trousers.
  • Don't use condoms or diaphragms with spermicidal lube on them – try non-spermicidal lube or a different type of contraception.

Cranberry and D-mannose

The balance of evidence suggests a lack of benefit for the use of cranberry products or D-mannose for the prevention of urinary tract infections. There is some conflicting data but it would not generally be recommended.

Also, be aware that evidence is inconclusive about whether probiotics (lactobacillus) reduce the risk of UTI in people with recurrent UTI.

Read more about cranberries and UTIs and D-mannose and UTIs

Learn more

Urinary tract infection Ministry of Health, NZ, 2017
Recurrent cystitis in women Patient Info, UK, 2016
Urine infection in men Patient Info, UK, 2016
Urine infection in older people Patient Info, UK, 2016


Reviewed by

Jeremy Steinberg is a GP with special interests in musculoskeletal medicine, evidence-based medicine and use of ultrasound. He's been reviewing topics for Health Navigator since 2017 and in his spare time loves programming. You can see some of the tools he's developed on his website.

Credits: Health Navigator Editorial Team . Reviewed By: Dr Jeremy Steinberg, FRNZCGP Last reviewed: 16 May 2019