Chlamydia is a sexually transmissible infection. Many people who are infected do not have symptoms of infection but can still spread the disease. Chlamydia can lead to infertility, and other complications if not treated.​

Last updated: 01 July 2012

What is Chlamydia?

Chlamydia is a sexually transmissible infection. It is caused by bacteria called Chlamydia trachomatis. Many people who are infected with the bacteria do not have symptoms but can still transmit it. Chlamydia can affect the urethra (the urine passage), cervix (the neck of the womb), rectum, anus, throat, and eyes. If chlamydia is not properly treated it can cause serious complications.

In women complications include:

  • Pelvic inflammatory disease (PID). This is when the reproductive organs that are situated in the pelvis become inflamed
  • Pelvic adhesions and chronic pelvic pain
  • Infertility due to damage to the fallopian tubes (by scar tissue)
  • Ectopic pregnancy (when the pregnancy develops in the fallopian tubes instead of in the uterus).

In men complications include:

  • Recurrent urethritis
  • Epididymitis (which involves the tube to the testes).

In women and men complications include:

  • Arthritis
  • Conjunctivitis and uveitis (eye inflammation)
  • Proctitis (inflammation of the rectum).

What are the symptoms?

Symptoms can occur within 2-14 days after infection. However, a person may have chlamydia for months, or even years, without knowing it.

In women

If a woman has chlamydia, she may notice:

  • Cramps or pain in the lower abdomen
  • Bleeding between regular periods
  • Pain when passing urine
  • Bleeding or pain during or after sex
  • A change in her vaginal discharge.

In men

If a man has chlamydia, he may notice:

  • A discharge from the penis
  • Pain when passing urine
  • Swollen and sore testicles.

In men and women

Infection of the anus can occur but usually goes unnoticed. Occasionally it can cause anal pain or discharge.

How is it spread?

Chlamydia is spread by having vaginal, anal or oral sex with someone who has the infection. Chlamydia can be transmitted even when there are no noticeable symptoms.

If a mother has chlamydia, her baby can become infected during birth.

Who is at risk?

The people who are most at risk of catching chlamydia are:

  • young sexually active men and women
  • anyone who has recently changed sexual partners
  • anyone who has recently had another sexually transmitted infection.

If you have symptoms you need to get a sexual health check as soon as possible so that you can be treated, if needed. Even if you don't have symptoms but have been having unsafe sex, it is still important to have a sexual health check from time to time, to find and treat any infections and to prevent spread to other people. People can be infected with several different sexually transmissible infections at the same time. Having a sexually transmissible infection makes it easier to pick up a new HIV infection. For people who are HIV positive, having a sexually transmissible infection makes it easier to pass on HIV to sexual partners.

More information about sexual health checks can be found at Sexual Health Check-up.

How is it prevented?

Using a condom correctly for vaginal or anal sex can significantly reduce the risk of getting chlamydia and other sexually transmitted infections. Always use condoms with new or casual partners.

You should not have sex with anyone who has been diagnosed with chlamydia, even using a condom, until 7 days after treatment is completed.

If you have chlamydia you should tell all your sexual partner/s. They may also have the infection and telling them allows them to be tested and treated so they don't spread the infection to others. Your doctor can help you decide who may be at risk and help you to contact them either personally or anonymously. The website www.letthemknow.org.au also provides advice and assistance in contacting partners.

If you are treated for chlamydia but your sexual partner is not, you could be re-infected. 

How is it diagnosed?

Chlamydia can be diagnosed by your local doctor or sexual health clinic. The doctor will take a urine sample which will be sent to a laboratory for testing. You should not pass urine for an hour before the test. 

How is it treated?

Chlamydia is easily cured by a single dose of antibiotics (called azithromycin). It is important to see your doctor or sexual health clinic to get tested and treated. If the symptoms return, return to your doctor or sexual health clinic.
If you have been diagnosed with chlamydia it is important to have another test 3 months after being treated so that a re-infection can also be treated.  

What is the public health response?

Laboratories are required to notify cases of chlamydia to the local public health unit. This information is confidential. Public health staff use this data to better understand who is at risk and help plan activities to prevent new infections in the future. Patients and their doctors should ensure that sexual partners who may have been exposed to chlamydia are contacted for assessment, counselling and treatment, if needed.

Further information

The Sexual Health Infoline Freecall 1800 451 624

The Sexual Health Infoline is a NSW Ministry of Health funded information and referral telephone line that is staffed by specialist sexual health nurses from 9:00am to 5:30pm weekdays.

The Infoline provides free and confidential sexual health support and information to community members and health professionals.

better to know

better to know provides information about sexually transmissible infections for Aboriginal women and men.

The Drama Downunder

The Drama Downunder provides information about sexually transmissible infections for HIV-positive and HIV negative gay men.

For further information please call your local Public Health Unit on 1300 066 055