Urinary tract infections (UTIs) during pregnancy

What is a urinary tract infection?

A urinary tract infection (UTI) is an infection of your urinary system. It can occur in different parts of your urinary tract, including your bladder (cystitis) and kidneys (pyelonephritis). The bacteria usually come from your gut (digestive system) where they don't cause problems.

You might have a bacterial infection in your urinary tract without any symptoms. This is known as an asymptomatic infection.

In your first trimester of pregnancy your doctor or midwife will check for UTIs by asking you to provide a urine sample.

UTIs can affect you whether you are pregnant or not. If you're pregnant, you have a 1 in 10 chance of getting a UTI. It's the most common type of infection in pregnancy. If you have a UTI while you're pregnant, you're more likely to get other, more harmful infections.

If a UTI isn't treated, you may develop kidney problems.

What are the symptoms of UTIs during pregnancy?

Common UTI symptoms in pregnancy are similar to those that happen with any UTI. They include:

• pain or a burning sensation when you pass urine (wee)
• feeling the need to urinate more often than usual
• urinating before you reach the toilet ('leaking' or incontinence)
• feeling like your bladder is full, even after you have urinated
• urine that looks cloudy, bloody or is very smelly
• pain in the lower abdomen or above the pubic bone
• fever

You might also experience symptoms that feel like early labour such as cramping.

If the infection has moved to your kidneys, you may also have:

• a fever (temperature above 38℃)
• back pain
• vomiting

What are the common causes of UTIs?

Your urinary tract is normally free of bacteria. If bacteria get in and multiply, they can cause a UTI. Some things that increase your chance of getting an infection are:

• being sexually active more than 3 times a week, which can increase the amount of bacteria around your genital area
• having problems emptying your bladder completely
• having diabetes, as the sugar in your urine may help bacteria to grow
• smoking

During pregnancy, your body goes through many changes. Some of these changes increase your chance of getting a UTI or getting recurrent (repeated) infections.

These changes to your body include:

• changes to your hormones which can mean you need to wee more often
• pressure from the weight of your uterus, which can stop your bladder filling properly and weaken your pelvic floor muscles
• changes to your urine pH (how acidic it is), which may help bacteria grow
• weakened immune system — which can lower your antibody defences against infection
• tubes that carry urine from your kidneys to your bladder become wider, which makes it easier for bacteria to get into your kidneys

If you have gestational diabetes, there is more sugar in your urine which allows bacteria to grow.

When should I see my doctor?

See your midwife or doctor if you have any symptoms of a UTI.

It's important not to delay getting antibiotics. An infection can develop quickly and can lead to problems for you and your baby.

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How are UTIs diagnosed?

Your doctor can diagnose a UTI from a urine sample. The sample is checked for bacteria in a laboratory. This can be done by seeing if bacteria grow or by looking at the sample under a microscope.

Your doctor will also ask about your symptoms and may do a physical examination.

Everyone who is pregnant will be offered a urine test, usually at their first antenatal visit or soon after. This is a routine screening test and might find an infection even if you have no symptoms.

You may need to repeat the urine test if:

• you had UTIs in the past
• you have symptoms of a UTI
• your previous urine sample had an unclear result
• your doctor thinks you are at high risk of developing a UTI

If you have many UTIs, you may need more tests, such as an ultrasound of your kidneys.

How are UTIs treated during pregnancy?

UTIs are treated with antibiotics that are safe in pregnancy. Your doctor will choose which antibiotic to give you based on the type of bacteria in your urine sample.

If your doctor is concerned about your UTI, they may give you an antibiotic right away, and then possibly switch to a different one after your test results come back.

If you have had many infections or many of your urine samples had bacteria, your doctor may prescribe regular antibiotics in your pregnancy to stop infections from happening. This is called prophylaxis.

Your doctor or midwife may recommend another urine test a few weeks after you finish your antibiotics to make sure that the infection is gone.

Asymptomatic UTI treatment

If bacteria are found in your urine during a pregnancy screening test, your doctor will decide if you need treatment. It's important to treat asymptomatic UTIs to prevent future issues for you or your baby.

What are the complications of UTIs during pregnancy?

A bladder infection is more likely to become a kidney infection if you are pregnant. Kidney infections during pregnancy can be serious and may cause problems for both you and your baby.

Having bacteria in your urine (even if you don't have pain or other symptoms) is linked to a condition called pre-eclampsia.

Pre-eclampsia is a serious medical condition that happens during pregnancy. It causes high blood pressure and can affect many body organs, including your:

• liver
• kidney
• brain

If left untreated, it can lead to serious problems for you or your baby, but early treatment stops these problems.

A kidney infection can cause:

• sepsis (severe infection)
• blood pressure problems
• kidney damage

Is there a risk to my baby?

If you have a UTI or a kidney infection while you're pregnant, your baby has a higher risk of an early birth or being born underweight. This risk goes away when your infection is treated.

The best way to keep your baby safe is to go to all your antenatal appointments with your doctor or midwife.

Can I prevent UTIs?

You can lower your chance of developing a UTI during pregnancy by:

• drinking plenty of fluids, especially water
• going to pass urine (wee) when you feel the need, and not delaying
• urinating right after sex
• wiping from the front to the back after going to the toilet
• showering instead of having a bath
• avoiding douching and using sprays or powders in your genital area

Resources and support

For more information on UTIs, visit the Kidney Health Australia page on UTIs.

Mothersafe NSW has an information sheet about urinary tract infection in pregnancy.