Urinary tract infection (UTI)

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Key points to remember

  • a urinary tract infection (UTI) is an infection in the wee (urine)
  • UTIs are common in children
  • UTIs can cause children to have high temperatures and become unwell
  • sometimes UTIs can make children seriously ill, especially babies and young children - see your doctor or after hours medical centre urgently if that happens
  • babies and children need investigation after a UTI to see if there is anything wrong with their urinary tract 

What is the urinary tract and how does it normally work?

The urinary tract is the kidneys, ureters, bladder, and urethra.

The kidneys filter and remove waste and water from the blood to produce urine. The urine travels from the kidneys down two narrow tubes called the ureters. The urine is then stored in the bladder.

When your child wees, urine flows out of the body through the urethra, a tube at the bottom of the bladder. The opening of the urethra is at the end of the penis in boys and in front of the vagina in girls.

Urinary tract front Urinary tract side male Urinary tract female side

Front view of urinary tract

Side view of male urinary tract

Side view of female urinary tract

See Acknowledgements for the above graphics.

What is a UTI?

A UTI (urinary tract infection) is an infection in the wee (urine). It usually starts in the bladder and sometimes affects the kidneys.

What causes a UTI?

A UTI usually develops when germs (bacteria) from the poo, which are on the skin, get into the urethra and into the bladder. This can happen to any baby or child and is not due to poor hygiene or changing.

What puts my child at risk of getting a UTI?

UTIs are common; approximately two percent of boys and eight percent of girls have a UTI in childhood.

Girls tend to have more infections because the urethra of a girl is shorter. Also, the opening of the urethra is closer to the anus (opening of the bowel). This makes it easier for germs from the poo to get up into the urethra and bladder.

There are some conditions which put babies and children at higher risk of UTIs:

  • any blockage or malformation of the urinary tract system 
  • urinary reflux - if your baby or child has urinary reflux they are at risk of UTIs Children who have constipation are also at higher risk of developing a UTI as constipation affects bladder emptying

See the following fact sheets on this website:

What are the signs and symptoms of a UTI?

Children with a UTI may experience the following symptoms:

  • pain on doing wee
  • wanting to wee frequently (but not doing much)
  • pain in the lower part of the stomach or side
  • smelly wee
  • cloudy wee
  • blood in the wee
  • vomiting
  • fever
  • feeling generally unwell often with loss of appetite
  • bedwetting, if previously dry
  • wetting during the day when previously dry

Babies and young children can't tell you about their discomfort on doing wee and you may not notice them going more frequently. Signs of a UTI in babies and young children can include:

  • fever (with no obvious cause such as a rash or cough)
  • irritability
  • poor feeding
  • vomiting
  • being lethargic (very tired and lacking energy) and ‘not quite right’
  • poor weight gain
  • prolonged jaundice in newborn babies

Sometimes a simple UTI can become more serious in young babies or children when the infection spreads to involve the kidneys or spreads into the blood stream. If this happens, you need to see your GP (general practitioner) or after-hours medical centre urgently. Signs of this can include:

  • high fever
  • abdominal pain
  • persistent vomiting
  • shivering
  • drowsiness

How is a UTI diagnosed?

Testing your child’s urine is the only way to know for sure if they have a UTI.

See the following fact sheet on this website:

What is the treatment for a UTI?

Antibiotics are the main treatment for UTIs. Treatment is usually for five to seven days (unlike treatment for UTIs in adults which may only require one to three days of antibiotics).

Encouraging your child to drink more fluid may help, and if they are in discomfort, pain relief (paracetamol) can be given. You must follow the dosage instructions on the bottle. It is dangerous to give more than the recommended dose.

Young babies or children who are very unwell with a UTI usually need to be admitted to hospital for IV antibiotics (given directly into a vein). 

See the following fact sheet on this website:

Your child's symptoms should start to improve after 48 hours of antibiotic treatment. 

In young babies, a small dose of antibiotics may be prescribed (to be taken once a day, usually at bedtime) to prevent a further UTI. Your baby may need to take the antibiotics until follow-up tests are completed.

What other tests may be needed?

If your child has had a UTI, they may need some of the following investigations to find out if there are any problems with their urinary tract:

  • renal ultrasound scan - all babies and pre-school aged children with their first UTI should have an ultrasound scan of their urinary tract. This is done to find out if there are any blockages and to check if the kidneys are normal in shape, size and position
  • MCU (micturating cysto-urethrogram)  if a condition called urinary reflux is suspected. This test is not routinely done.
  • DMSA renal scan - to check for scarring and function of the kidneys which may be caused by recurrent UTIs.  This test is only done in some children.

See the following fact sheets on this website:

Your GP (general practitioner) may organise these tests, or may refer you to one of the following:

  • your hospital’s paediatric outpatient department
  • a paediatrician (children’s doctor)
  • a paediatric urologist (doctor who specialises in the surgical treatment of the urinary tract in children)

When should I seek help?

You should see your family doctor if:

  • your baby or child is experiencing any of the signs and symptoms that indicate they have a UTI
  • your baby or child has a UTI and their symptoms are not improving after 48 hours (as they may need a different antibiotic)

You should see your GP or after hours medical centre urgently if your baby or child has one of the following

  • high fever
  • abdominal pain
  • persistent vomiting
  • shivering

Dial 111 within New Zealand for urgent medical help if you are very concerned about your child. Use the appropriate emergency number in other countries.  

What can I do to help prevent UTIs in my child?

Parents often want to know what they can do to prevent UTI’s. Some of the following suggestions may help some children.

Encourage your child to go to the toilet when they feel the need (children who hold on a long time before passing urine are more at risk of UTIs) and to take enough time to empty their bladder properly

  • make sure your child drinks plenty of fluids especially water with meals, and during hot weather
  • teach girls to wipe their bottoms from front to back rather than back to front (to reduce the spread of germs from the bowel to the opening of the urethra)  
  • treat any constipation (children who have constipation are at higher risk of developing a UTI)

Try to avoid anything that may cause irritation to your child's bottom, as this can encourage the bacteria to grow in the area and lead to UTIs. This can include the following:

  • avoid giving your child bubble baths or letting them sit in soapy bath water, especially if they have sensitive skin
  • check for threadworms, which are very common in children, and consider treating your child every six months
  • encourage girls to wear loose cotton underpants, as some synthetics can be harsh on sensitive skin

There is evidence that uncircumcised boy babies seem a little more likely to get UTIs because germs may grow under the foreskin in drops of urine. But infections that are caused by this are rare and most doctors will not advise circumcision for this reason alone.

See the following fact sheets on this website:


This fact sheet has been adapted from:

Royal Children's Hospital logo
  • Paediatric Outpatient Department. Christchurch Hospital. Canterbury District Health Board. 2002. Urine infections and ureteric reflux.
  • Children’s Unit. Waikato District Health Board. 1999. Urinary tract infections.
Graphics of the urinary tract have been reproduced from NKUDIC (the National Kidney and Urologic Diseases Information Clearinghouse), United States. (These images are in the public domain; reproduction permitted).
This page last reviewed 27 March 2013
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Printed on 28 May 2015. Content is regularly updated so please refer to www.kidshealth.org.nz for the most up-to-date version
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