Are Antibiotics Safe for UTI in Pregnancy?

Written by

Kayleigh Maxwell

UTI Causes, Symptoms and Treatment Options During Pregnancy

While over half of women will experience a UTI at some point in their lifetime, UTI (also known as cystitis) affects approximately 8% of women who are pregnant. (1)

Asymptomatic bacteriuria (ASB) is also very common in pregnancy. This is when there are bacteria in your urinary tract but you are not actually experiencing any symptoms or signs of a UTI.

But why is the risk of UTI higher during pregnancy? How do you tell the difference between cystitis symptoms and pregnancy symptoms? And is it safe to be using antibiotics?

UTI causes during pregnancy 

Some of the risk factors for UTI in pregnancy are the same as those for non-pregnant women:

  • History of urinary tract infection

  • Anatomical differences

  • Harmful bacteria getting into the urinary tract during sexual activity

  • Bacterial imbalance caused by diet or digestive issues

  • Dehydration

And other UTI risk factors are pregnancy-specific (1),(2):

  • As the uterus expands, it puts pressure on the urinary tract

  • Hormonal changes can disrupt fluid passing from the kidneys to the bladder, meaning that urine is stored for longer, leading to a buildup of bacteria

  • Medical procedures during pregnancy which involve the insertion of a catheter or other device can also introduce bacteria to the urinary tract

The anatomical and hormonal changes that occur during pregnancy are more likely to be risk factors for cystitis between weeks 6 to 24 of pregnancy.

Another possible risk factor is the balance of different bacterial species within the microbiomes (communities of bacteria) in your body. That being said, research is lacking on possible changes that may occur, so it isn’t possible to make any certain conclusions about this one yet. (3)

Signs of UTI in pregnancy

If you have a urinary tract infection, the symptoms will also be similar to those of UTI in non-pregnant women. Here are the most common symptoms (4):

  • Feeling a strong need to pee very frequently

  • Stinging or burning when you pee

  • Pain in your lower tummy

  • Cloudy urine

  • Blood in your urine

  • Smelly urine

Similarly, symptoms of a kidney infection (an upper UTI) are the same in pregnant and non-pregnant women, the most common being back pain, fever and chills. (2)

As mentioned before, pregnant women are more at risk of having bacteria in their urine even in the absence of symptoms (AKA asymptomatic bacteriuria), and if infection goes undetected it could lead to complications for both the mother and the foetus.

Infection puts the mother at greater risk of anaemia, pre-eclampsia and inflammation or irritation of the uterus lining (endometritis) post-partum. Risks to the foetus include restricted growth and preterm delivery. (1)

You might be concerned that you have experienced, or are experiencing, one or more of the symptoms listed above, as there is some overlap between cystitis symptoms and pregnancy symptoms. For example, it is very common to experience a frequent urge to pee, or discomfort in the tummy or back when pregnant. And in pregnancy the sensations that you experience may change extremely frequently. 

But if you are experiencing multiple signs of a UTI and are worried that you may have an infection, it is important that you do a urine test, which you can do at home with the TestCard UTI test kit (available at If your symptoms become more severe or you begin to experience symptoms of an upper UTI (e.g. vomiting, fever, chills), it is important that you seek help from a medical professional straight away.

Treatment options

So a dipstick urine test shows that there is a high likelihood that you have a urinary tract infection - what do you do next? 

You should speak to your doctor straight away.

NICE (the National Institute for Health and Care Excellence) advises doctors to conduct a urine culture and a susceptibility test when testing for UTI in pregnant women. (5) If there is an infection, this helps them decide which antibiotic will be the most effective and safest at getting rid of the infection. 

However, they will most likely start you on a course of antibiotics straight away while waiting for the test results, and change the antibiotic later on if necessary. 

How long do antibiotics take to work?

The following antibiotic treatment is recommended by NICE (although results of a previous urine culture or susceptibility test may influence the choice) (5),(6):

  • First choice - Nitrofurantoin for a course of 7 days

  • Backup options (if there is no improvement with Nitrofurantoin) - Cefalexin or Amoxicillin for a course of 7 days 

Studies show that UTI symptoms can become much less severe after three to four days on antibiotics. (7),(8) That being said, it is extremely important to complete the whole course of the antibiotics you are prescribed, even if symptoms clear up, so that none of the bacteria causing the infection are left behind and able to cause another infection.

Are antibiotics safe?

Although there are risks associated with antibiotic use, (9) the most important thing is that complications resulting from more severe infection are avoided, and the most effective treatment for cystitis in pregnancy are antibiotics. 

The antibiotics prescribed by a medical professional for cystitis will be those that are safest during pregnancy, and will be informed by an antibiotic susceptibility test, which helps the doctor to make a decision about the most appropriate antibiotic to prescribe.

For more information about how antibiotic treatment decisions are made within the NHS for UTI during pregnancy, there are some useful flow diagrams in these NHS guidelines.

How to prevent a UTI

One way to avoid the use of antibiotics is by preventing the development of an infection in the first place. There are a number a key steps you can take to prevent a urinary tract infection while you are pregnant 4:

  • Wiping from front to back avoids the travel of bacteria from the gut to the vagina, and then the urinary tract

  • Try as best you can to fully empty your bladder when you pee, to ensure that bacteria doesn’t hang around in the urinary tract

  • Keep hydrated so that any harmful bacteria are flushed out of your system

  • Oldie but goodie - pee after sex! This also flushes away potentially harmful bacteria, which can enter the vagina and then urinary tract during sexual activity

  • Don’t wear clothing that is too tight - wear looser, more breathable clothing including cotton underwear

  • Keep the area clean and dry, and avoid the use of soaps, vaginal lotions or bubble bath products. These can affect the functioning of ‘good’ bacteria which is needed to counteract the bad

  • Eat a healthy, balanced diet. Ingesting plenty of vitamins and minerals will help to balance your microbiome, and also prevent constipation, another risk factor for UTI.

For more information on general prevention strategies visit our UTI prevention blog, and for more tips on preventing cystitis with dietary changes, check out our Nutrition and Hydration blog.

Asymptomatic bacteriuria (ASB)

Regardless of the symptoms you experience, you will likely be tested occasionally for urinary tract infection while pregnant. This is due to the prevalence of ASB sitting at around 10%, meaning that around 10% of pregnant women will test positive for a significantly high level of bacteria in their urine even though they experience no signs of a UTI, like burning or stinging when peeing or having cloudy urine. (3) The risk factors mentioned above all contribute to this prevalence rate during pregnancy.

If you test positive for asymptomatic bacteriuria, a similar treatment pathway as above will be followed, and more details can be found in these NHS guidelines.

You may be wondering why asymptomatic bacteriuria needs to be treated at all, if you have no symptoms and feel otherwise fine. But if untreated, around 25% of pregnant women with ASB will develop a symptomatic UTI, and for around 50% the infection will spread to the kidneys. (2)

That being said, prescribing antibiotics for asymptomatic bacteriuria during pregnancy should be a decision made with care. Your personal medical history and personal preference for medication use should be taken into consideration, and you and your doctor should be able to make an informed decision together. 

There is also currently a push for research looking into whether shorter courses of antibiotics could be just as effective at treating cystitis. (9) But in the meantime… you can read up on the NICE recommendations, and if you have concerns about symptoms, want to know more about preventing UTI, or are worried about the implications of antibiotic use, don’t be afraid to speak to your doctor or pharmacist!



2 Habak, P. J., & Griggs Jr, R. P. (2019). Urinary tract infection in pregnancy.





7 Richards, D., Toop, L., Chambers, S., & Fletcher, L. (2005). Response to antibiotics of women with symptoms of urinary tract infection but negative dipstick urine test results: double blind randomised controlled trial. Bmj, 331(7509), 143.

8 Bleidorn, J., Gágyor, I., Kochen, M. M., Wegscheider, K., & Hummers-Pradier, E. (2010). Symptomatic treatment (ibuprofen) or antibiotics (ciprofloxacin) for uncomplicated urinary tract infection?-results of a randomized controlled pilot trial. BMC medicine, 8(1), 1-8.

9 Storme, O., Tiran Saucedo, J., Garcia-Mora, A., Dehesa-Dávila, M., & Naber, K. G. (2019). Risk factors and predisposing conditions for urinary tract infection. Therapeutic advances in urology, 11, 1756287218814382.