Causes

UTIs are usually caused by faecal bacteria entering the urinary tract through the urethra. Risk factors for bacteria getting into the bladder include:

• Not drinking enough fluids
• Not keeping the genital area clean and dry
• Having sex
• Pregnancy
• Conditions that block the urinary tract – such as kidney stones
• Conditions that make it difficult to fully empty the bladder – such as an enlarged prostate in men and constipation in children
• Urinary catheters (a tube in the bladder used to drain urine)
• Having a weakened immune system – for example, people with diabetes or people having chemotherapy.

Women have a shorter urethra than men, which puts them at greater risk of bacteria reaching the bladder or kidneys and causing an infection.