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Author - Chris K

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UTIs After Sex: Why It Happens and How to Prevent It

Many of us have been there. The burning sensation, the urge to urinate and knowing you’ll have to take another trip to the doctor likely at the most inconvenient time, or even when a doctor is not available. We know that frequent sex is a risk factor for susceptibility to urinary tract infections, but we aren’t quite ready to become celibate just to avoid UTIs!

UTIs are incredibly common and 20-30% of women who have had a UTI will have a recurrence¹. So, we take a look at why UTIs are more likely to happen after sex and whether there is anything you can do to reduce the risk.

 

Why do UTIs happen after sex?

E. coli bacteria, which live in the bowel, cause most UTIs, as sexual activity can move bacteria to the urethral opening. UTIs can occur after sex because the increased movement causes bacteria from your bowel e.g. E. coli to be transferred from your anus to the vagina and urinary tract. If bacteria start colonising the ‘wrong’ space, such as your vagina or urinary tract, this can lead to an unbalanced microbiome and can cause an infection.

In some cases, microbes on the penis or in the mouth can also be transferred to the vagina or urinary tract during sex. If you keep getting UTIs after having sex with a regular partner, antibiotic therapy for your partner may help. You can also check their penile or oral microbiome.

 

Can you prevent UTIs after sex?

It may not always be possible to completely prevent UTIs after sex if this is a trigger for you and you want to continue being sexually active. Some women may feel they should stop having sex to avoid UTIs, but this can have a big impact on your quality of life! It’s therefore important that we look for other ways to manage the recurrence of UTIs.

There are promising ways to test and manage the balance of your intimate microbiome (or your partner’s) in the long term, which we explore in more detail below.

Some women also find the following tips help to lower their risk of getting an infection.

Consider your contraceptive options

If you frequently get UTIs after sex, you might consider avoiding spermicide-coated condoms or diaphragms if you can safely do so, as there is strong evidence that these types of contraceptives are a risk factor for recurrent UTIs.

The main active ingredient in spermicides is toxic to lactobacilli (protective microbes in your vaginal microbiome) but not E. coli (invading microbes)², which can potentially increase the colonisation of the vaginal microbiome. A study of premenopausal women³ found that E. coli colonisation was found to be significantly increased in 75 women using diaphragm-spermicide contraception with no change in E. coli colonisation in 103 women using oral contraceptives.

There have also been some suggestions of a potential link between intrauterine devices (IUDs) and UTIs due to copper being an antimicrobial metal, as this could theoretically have an effect on the microbiome. For example, one study found that a copper intrauterine device (IUD) use may increase bacterial diversity and decrease the relative abundance of lactobacilli⁴ compared to other contraceptive options.

We understand there are other factors at play when choosing your preferred contraceptive method, and we all react differently, so it’s worth speaking to your doctor before switching to a new method of contraception.

Avoid mixing types of sex in one session

Sex should be enjoyable, and variety is the spice of life for many of us! However, mixing lots of types of sex in one session – such as vaginal, anal, oral and the use of sex toys – and trying out lots of different positions in one go – is likely to increase your risk of contracting a urinary tract infection. This is because microbes can easily transfer between these intimate areas.

Make sure sex toys are cleaned (gently) before/after use

If you regularly use sex toys in the bedroom, make sure you clean these with a gentle cleanser before and after use to limit the chance of bacteria transferring from the toy to your urogenital system. If you notice you get a UTI after using a specific toy, you might also consider updating your collection. It gives you an excuse to buy a new one after all!

Urinate before and after sex

Urinating regularly, particularly before and after sex, is thought to be helpful in limiting the risk of UTIs because it helps to flush out bacteria in your urinary tract. As a woman’s urethra is shorter, the bacteria don’t have to travel as far to cause an infection, so it’s best to try and flush them out sooner rather than later.

 

How do I manage UTIs after sex?

If you contract a UTI, you should speak to your healthcare provider first who will help to advise you on treatment options. There are some other things you can do, however, that can boost your natural defences and may help reduce the risk of you getting a UTI after sex in the future!

 

Check your partner’s microbiome

If you are having sex with a regular partner and keep contracting a UTI, it is worth checking if they could be the source of the UTI-causing bacteria such as E. coli. Without putting the blame on anyone, it might be them, not you. It’s possible to test their oral and penile microbiome to see if your partner could be transferring bacteria to you during sex or maybe see if they are happy to take the same round of antibiotics you are taking to get rid of the bugs.

Test your own microbiome

Next to the usual urine dipstick tests, there are more advanced DNA testing kits, which allow you to check the type and quantity of the type of microbes (fungi, bacteria etc) present in your urine and vaginal samples. While those tests are more expensive and it usually takes two weeks to receive the results, they might be worthwhile to gain a deeper understanding of what’s going on. There are also tests which allow you to check for antimicrobial resistance of the bacteria present. Taking these tests back to your doctor might give them a better idea of what antibiotics are best to use.

It will also allow you to check the balance of lactobacilli vs other invading microbes. If there are too few ‘good’ microbes, this may increase your chances of getting a UTI after sex.

Try probiotics or other alternatives

If you discover that your or your partner’s microbiome is unbalanced, you can take probiotics to try and help increase the presence of good bacteria, there are a number of oral or topical solutions available that could be a good option. Alternatively you can speak to your healthcare provider

 

UTIs are common after sex, but there are triggers to avoid and some things you can try to improve the balance of your intimate microbiome and reduce your chances of contracting a UTI.

Do you often get UTIs after sex? Let us know your experiences in the comments below and if you have any tips for other readers – we would love to hear your thoughts!

 

Sources

  1. https://cks.nice.org.uk/topics/urinary-tract-infection-lower-women/background-information/prevalence/
  2. https://www.nature.com/articles/s41585-018-0106-x
  3. https://pubmed.ncbi.nlm.nih.gov/10669343/
  4. https://www.nature.com/articles/s41467-023-36002-4
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