What is chlamydia?

Chlamydia is a common treatable sexually transmitted infection (STI), that is caused by a bacterium (germ) called Chlamydia Trachomatis. It is mainly spread from person-to-person through sexual contact with the vaginal fluids or semen (the fluid that comes out of the penis) of someone who has chlamydia. The most common symptom is discharge; however, most people have no symptoms at all.

Chlamydial infection can affect:

  • The uterus (womb) and fallopian tubes (the tubes connecting the ovaries to the womb).
  • Vagina and cervix (the entrance to the womb)
  • Urethra (the tube where urine comes out)
  • The rectum (back passage)
  • Testicles and prostate (a male sex gland)
  • More rarely the eyes, lungs, and throat.

Anyone who is sexually active can get it and pass it on. If left untreated chlamydia can lead to severe complications, especially in women, including infertility (inability to get pregnant). This is why it is important to know about chlamydia, so it can be quickly and effectively treated.  

How common is chlamydia?

  • Chlamydia is the most common STI in the UK.
  • 3 to 7 in 100 sexually active young people in the UK are infected.
  • Although it can affect any age group, it is most common amongst those under the age of 25.

How do you get chlamydia and pass it on?

Chlamydia is most commonly spread through:

  • Unprotected (no condoms) vaginal or anal sex.
  • Sharing sex toys that are unwashed or not covered (with a new condom each time they are being used).
  • Giving or receiving oral sex without protection.
  • Unprotected genital rubbing.

Less commonly it is spread through:

  • Semen or vaginal fluid coming into contact with the eye, causing conjunctivitis (an eye infection).
  • Passed from a pregnant woman to her baby during birth, resulting in pneumonia (a chest infection) and/or conjunctivitis.

It is important to note that you cannot get chlamydia from hugging, kissing, swimming pools, toilet seats, sharing baths or towels, or from sharing plates, cups, or cutlery.

What increases the risk of getting chlamydia?

  • Having unprotected sex (including oral and anal).
  • Sharing unwashed and uncovered sex toys.
  • Having a sexual partner who is infected with chlamydia.
  • Being under 25 years old.
  • Having more than one sexual partner in the last year.
  • Having recently changed sexual partner.
  • Having other STIs.

Will you know if you have chlamydia?

  • Those infected may not be aware as one half of infected men (5 out of 10) and around 70% (7 out of 10) of infected women have no symptoms.
  • This means those infected can have it for months or even years, without even being aware.
  • This is why it is important for all sexually active people who are at risk, to get tested even if there are no symptoms.
  • If symptoms are present the main symptom is increased discharge.

What are the symptoms of chlamydia in women?

  • Increased vaginal discharge
  • Lower abdominal pain (pelvic tummy pain).
  • Pain or burning when passing urine.
  • Pain during or after sex.
  • Heavier periods.
  • Bleeding between periods.
  • Bleeding during or after sex.

What are the symptoms of chlamydia in men?

  • Discharge from the tip of the penis.
  • Pain or burning when passing urine.
  • Pain in the testicles or tip of penis.

What are the symptoms of chlamydia in both men and women?

  • If chlamydia infects the eyes this can cause eye pain, swelling, irritation and/or discharge.
  • If the infection is in the rectum (back passage) there may be discharge and pain.

How to get tested for Chlamydia

Testing for chlamydia is easily accessible and available for free from a wide range of services including:

  • GP surgery.
  • Genitourinary medicine (GUM) clinics (sexual health clinics).
  • Some pharmacies.
  • Online GP and sexual health services which provide postal home kits (although there may be a fee).
  • In England, there is a national chlamydia screening program for all sexually active men and women under the age of 25. This involves having a test every year to check for chlamydia before there are any signs or symptoms.

What does the test involve?

For women:

  • A vaginal swab (a little stick with a small ball of cotton wool on the end) is inserted about 5 cm into the vagina and rotated (turned) gently for a 10-30 seconds.
  • The aim is to obtain discharge and cells for testing.
  • The test is usually painless and can be self-directed or done by a healthcare professional.
  • Other tests include:
    • Taking a swab from the cervix (the entrance to the womb) by a healthcare professional.
    • A urine test.

For men:

  • The most common test is a urine test.
  • Another option is taking a swab from around the entrance of the urethra by a healthcare professional.

Other tests include:

  • A swab from the rectum if there has been anal sex
  • A throat swab if there has been oral sex.
  • Testing for other STIs.

Does chlamydia always show up on a test?

  • The recommended tests can detect chlamydia in over 95% of cases.
  • There may be a small chance that the test will give a negative result in a person who does have the infection.
  • If a test is negative but the person develops signs or symptoms of chlamydia, a repeat test is advised.

Who should get tested for chlamydia?

  • Younger people (less than 25 years of age) who are sexually active should:
    • Have a yearly test as part of the national chlamydia screening (available in England only).
    • Have a test if they have been treated for chlamydia in the past three months.
  • Those who have concerns about sexual exposure.
  • Those with symptoms which may indicate an infection.
  • The sexual partners of people with suspected or confirmed chlamydia.
  • Those who in the past year have had more than one sexual partner.
  • Mothers of infants with chlamydial infection
  • Those who are identified as at risk of STIs who are being fitted with an intrauterine contraceptive device (IUCD – the coil).
  • Those undergoing a termination of pregnancy (abortion).
  • Those attending a genitourinary medicine (GUM) clinic (specialist sexual health clinic).

Should you get tested for other STIs?

  • It is strongly advised to be screened for other STIs, including:
    • Gonorrhoea (the second most common STI).
    • Hepatitis B.
    • HIV.
    • Syphilis.
  • This is because those who have chlamydia are more likely to also have other undetected STIs, especially gonorrhoea.
  • The earlier other STI’s can be picked up and treated, the less risk there is of developing complications from these infections.

How is chlamydia treated?

  • The treatment for chlamydia is with antibiotics. Antibiotics fight the bacteria that causes the infection.
  • Antibiotics can be started by a GP, but referral to a sexual health clinic is advised to get further STI testing and to inform all current and recent sexual partners.

Treatment is given for:

  • Those who test positive for chlamydia.
  • Those who have a high chance of having the infection, for example those who have signs or symptoms that strongly suggest chlamydia although the results of the test are not yet back.
  • Those who have a sexual partner who has tested positive for chlamydia.

Antibiotics used to treat chlamydia are:

  • Doxycycline (the most effective and commonly used).
  • Azithromycin (safe in pregnancy).
  • Ofloxacin (only for non-pregnant adults).
  • Amoxicillin (safe in pregnancy).
  • Erythromycin (safe in pregnancy).

How will you know your infection has been effectively treated?

  • When taken correctly, antibiotics are successful in treating over 95% of chlamydial infections.
  • If symptoms are present, they should improve as follows:
    • Within one week both discharge and pain when passing urine should improve.
    • Within two weeks testicular or lower abdominal pain (tummy pain) should have resolved.
    • Heavier periods, bleeding between periods and bleeding during or after sex should improve by the next period.

Do you need to get a repeat test to check that the infection is gone?

Only the following people need to undergo a repeat test 3 weeks after treatment to check the infection is gone:

    • Currently pregnant.
    • Has persistent symptoms.
    • Confirmed chlamydial infection in the rectum (back passage).
    • Has not correctly taken the antibiotics.
    • May have come into contact with chlamydia again.
    • Had unprotected sex with a partner before the treatment was finished.

Do you need to inform your partner?

  • All current and recent sexual partners need to be informed.
  • This is important, so that they can be tested and treated.
  • The person seeking treatment can inform their sexual partner(s) themselves or with permission the clinic can inform them.
  • If the clinic informs the sexual partner(s), they will not mention any names (for confidentiality purposes). They will just inform the person that they may have been exposed to a STI and to go for a check up.

After treatment when can you safely have sex again?

To prevent re-infection those treated for chlamydia should:

  • Not have oral, vaginal, or anal sex, or use sex toys or have genital contact with other persons, until seven days after they and their partner(s) have all finished the treatment and any symptoms have gone.

How do you reduce the risk of getting chlamydia?

  • Use condoms (male or female) every time for vaginal or anal sex.
  • For oral sex or genital contact use a condom to cover the penis, or a latex or polyurethane (soft plastic) square to cover the female genitals.
  • Avoid sharing sex toys, but if they are shared, wash them, or cover them with a new condom before anyone else uses them.
  • Limit the amount of different sexual partners.
  • Ensure regular STI testing of all parties before starting any new sexual relationships.

What complications can occur in women with chlamydia?

  • If left untreated, the infection can cause serious complications.
  • This is because chlamydia can affect the uterus and fallopian tubes.
  • This can cause a condition called: pelvic inflammatory disease (PID).
  • PID is a condition where there is damage and scarring overtime to the uterus and fallopian tubes.
  • 10-40 women in 100 with chlamydia develop PID.
  • It can develop suddenly with acute lower abdominal pain, pain during deep penetrative sex and vaginal bleeding after sex or between periods.
  • It can also develop slowly over months or years without any symptoms.
  • It can lead to the following:
    • Infertility
    • Pregnancy complications.
    • Chronic pelvic pain.
    • An increased risk of ectopic pregnancy (a condition, where the pregnancy develops in a fallopian tube and not the womb, which is life-threatening).

If there is concern that chlamydia could be causing PID or affecting fertility it is important to speak to a doctor or another qualified healthcare professional.

What are the important signs or symptoms that may suggests a more severe (complicated) chlamydia infection?

  • Fevers or a temperature.
  • Persistent pelvic pain.
  • Severe abdominal pain.
  • Difficulty becoming pregnant (infertility).
  • Pain during deep penetrative sex.
  • Abnormal vaginal bleeding.
  • Having an ectopic pregnancy. Symptoms may appear as lower pelvic pain especially on one side, vaginal bleeding (especially dark blood) and a missed period.

It is important to seek immediate medical attention if you are experiencing fevers or a temperature, severe pain and/or symptoms suggestive of an ectopic pregnancy.  

What other complications can occur in chlamydia infections?

In men untreated chlamydia can:

  • Cause inflammation (pain and swelling) of the testicles and prostate.
  • Possibly lead to reduced fertility.

In both men and women untreated chlamydia can lead to a rare medical condition known as: reactive arthritis. This causes the following:

  • Painful swollen joints.
  • Inflammation (pain, redness and swelling) of the eye and urethra (the tube where urine comes out).

It is important to know that the risk of developing complications is reduced if chlamydia is treated early, especially when showing no symptoms.

Chlamydia during pregnancy

Untreated chlamydia during pregnancy has been associated with the following problems:

  • Increased risk of miscarriage.
  • Infection of the uterus (womb) lining after the birth.
  • Premature (early) birth.
  • Less commonly, if passed from a pregnant woman to her baby during birth it can result in pneumonia and/or conjunctivitis.

There are a variety of antibiotics that can be safely used to treat chlamydia during pregnancy and whilst breastfeeding. If there are any concerns about chlamydia during pregnancy, a test can be easily requested from a midwife or in the same way as a non-pregnant person.