How to say: (Kla-mid-ee-a)

If you are between 16 and 24 years of age and would like to receive a free test kit in the post click here.

What is it?

Chlamydia is a sexually transmitted infection (STI) caused by the bacteria Chlamydia trachomatis. Since the mid-1990s, the number of people being diagnosed with chlamydia in the UK has been steadily increasing, and it is now the most commonly diagnosed STI.

Chlamydia affects both men and women. 1 in 10 sexually active young people under the age of 25 are thought to have chlamydia and therefore are most at risk, however, people of all ages can be affected.

As there are often no symptoms, people can live with chlamydia without knowing it for a long time, however, once the infection has been detected, it can be easily treated.

How do you get it?

You can be infected with chlamydia, or pass it on to someone else, during sex.

Chlamydia infects the cells inside the cervix (neck of the womb), the rectum (back passage) and the urethra (the urine tube). Once you’re infected, chlamydia can be passed on through semen or vaginal fluids.

The most common ways for people to get chlamydia is through vaginal or anal sex with an infected person without using a condom. Chlamydia can also be spread through oral sex or through sharing sex toys without washing them.

If infected semen or vaginal fluids come into contact with the eyes, this can cause conjunctivitis (an infection of the eye).

Chlamydia can also be passed from a mother to her baby during pregnancy and childbirth. This may cause the newborn baby to have conjunctivitis and/or pneumonia.

Even if you have had chlamydia before, and were treated successfully, you are still at risk of catching it again. Using a condom will greatly reduce your risk.

Chlamydia CAN NOT be caught from:

  • kissing,
  • sharing towels,
  • sharing cutlery, cups and plates,
  • or sharing toilet seats.

Signs and Symptoms

In many cases there are no symptoms associated with Chlamydia (especially in women), which means that people do not realise that they have the infection. If there are any symptoms, they usually appear 1-3 weeks after contact with an infected partner.


Approximately 70% of women with chlamydia have no symptoms, however, some women may experience some or all of the following;

  • unusual vaginal discharge
  • pain and/or burning when peeing
  • pain during and/or after sex
  • bleeding after sex or between periods
  • lower abdominal pain (pain in the lower belly)

If left untreated Chlamydia can spread to other reproductive organs. It can result in pain, especially in the abdomen (area below the belly button) and may cause pelvic inflammatory disease (PID). It can also lead to damage in the fallopian tubes (the tubes that take the eggs to your womb each month) and cause them to become narrowed or blocked. This could result in infertility (not being able to have a baby), or may cause an ectopic pregnancy (a pregnancy which is developing in the tube because it didn’t reach the womb). Ectopic pregnancy can be very serious and even life-threatening.


Approximately 50% of men with chlamydia have no symptoms, but those who do may experience some or all of the following;

  • difficulty, pain or a burning sensation when peeing
  • painful testicles
  • a white/cloudy or watery discharge from the penis
  • burning and itching within the urethra

Symptoms are caused by inflammation (swelling) of the tube that carries urine from the bladder to the tip of the penis (urethra) and due to inflammation of the tube leading from the testes to the penis (epipdidymis). Approximately half of all men with symptoms have impaired fertility (inability to have children).

Chlamydia can also infect the rectum (back passage) in both men and women. This does not usually cause any symptoms but if it does these may include rectal discomfort (itching and soreness in the back passage).

In rare cases, both men and women with chlamydia can develop a condition that affects the eyes (causing redness and irritation) and joints (swelling and pain). This is called Reiters syndrome.

Testing for Chlamydia

As most people with chlamydia won’t show any signs of being infected, the best way to find out is to have a test.

The test is FREE, simple and painless. You don’t even have to be examined.


You will need to give a urine (wee) sample. It is better if you do not wee for an hour beforehand.


You will either need to give a urine (wee) sample. It is better if you do not wee for an hour beforehand...

Or some places will ask you to give them a swab. The swab is like a large cotton bud. You put this inside your vagina, turn it around so it can absorb some of the fluid there.


Taking a test is private. No one else will know apart from the person who gives the kit to you and the people that test your sample and give you your results.

Sometimes the test looks for one infection...chlamydia, sometimes the test also looks for another common infection called gonorrhoea. Both are treatable and the person that gives you the test will tell you whether you are being tested for one or two infections. If you think you have another infection, then you might need different tests – call the sexual health helpline for more information (0800 567 123) or ask about other tests when you go for your screen.

There are different ways to get your results. This will be explained either by the person giving the test to you, or it will say on the kit.

If you are aged 24 or under and would like to receive a free test kit in the post click here.


The good news is that chlamydia is usually easy to treat with medicine (antibiotics).If you do have chlamydia, it is important:

  • the person or people you have had sex with since your last test are told that they need treating too. This can be arranged for you if you don't feel comfortable telling them.
  • you avoid having sex (oral or vaginal or anal) for 7 days after you and your partner have finished taking your medicine, otherwise you may re-infect each other.
  • you say if you are taking the contraceptive pill or if you are pregnant.



Where can I get tested?

You can get a test done at:

Local services »

More information

This page has been adapted from

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