What is chlamydia?

Chlamydia is a curable bacterial infection that usually shows no symptoms and is easily treated with antibiotics.

If it's left untreated, chlamydia can lead to more serious health problems. These include:

  • pelvic inflammatory disease
  • painful swelling of the testicles
  • complications with pregnancy and infertility (difficulty getting pregnant).

How chlamydia is transmitted

Chlamydia spreads through unprotected vaginal, anal and oral sex with someone who has the infection.

While it's not as common, chlamydia can also spread during other types of sex involving genital fluids. This includes sharing sex toys, mutual masturbation, or genital to genital rubbing.

Symptoms of chlamydia

Most people who have chlamydia don’t show any symptoms. If you do have symptoms, they usually show within a couple of weeks after you've had unprotected sex with someone who has chlamydia.

If you have a vagina, you may notice:

  • a change in vaginal discharge
  • crampy pain in the lower abdomen
  • menstrual changes including longer, heavier periods
  • pain when urinating (peeing)
  • bleeding or spotting between periods or after sex
  • pain during or after sex.

Chlamydia is a sexually transmissible infection or STI that is passed between partners during unprotected vaginal, anal and oral sex. Many people with chlamydia do not have any symptoms so they may not even know they have it.

It is the most common bacterial STI world-wide, especially among people aged 15 to 29 years.

Chlamydia can infect the cervix, throat, anus, eyes, and the urethra which is a thin tube connected to the bladder through which urine passes.

Without proper treatment, Chlamydia can spread further through the body, infecting the uterus and the fallopian tubes. These are the tubes that connect the uterus to the ovaries.

When the body detects an STI, the immune system tries to destroy the infection.
There are often no symptoms during this immune response, but sometimes the area can become inflamed and sore.

As the STI is killed and immune system cells die off, they sometimes form a discharge at the opening of the vagina.

The inflammation that occurs in the cervix, uterus or fallopian tubes is called Pelvic Inflammatory Disease or PID. PID can present as mild abdominal pain which can be missed if women mistake it for period pain. It can also cause pain or bleeding during or after sex.

PID can also cause scarring which can block the fallopian tubes and may result in infertility, as sperm released during ejaculation cannot travel through the tubes to fertilise the egg.

Damaged or scarred fallopian tubes can also impact on the process of moving a fertilised egg through the tube towards the uterus at the start of pregnancy.

The egg may then attach itself to the fallopian tube where it begins to grow.
This is called an ectopic pregnancy and can be very dangerous.

Chlamydia can also be passed from mother to baby during delivery, causing an infection in the newborn’s eyes.

Chlamydia and other STIs can be prevented by using condoms and water-based lubricant during sex, having regular sexual health check ups and ensuring you or your health provider notify your sexual partners if you are diagnosed with an STI.

If you have a penis, you may notice:

  • a discharge from your penis
  • discomfort or irritation at the tip of your penis
  • pain when urinating (peeing)
  • swollen and sore testes.

Chlamydia is a sexually transmissible infection or STI that is passed between partners during unprotected vaginal, anal and oral sex. Many people with chlamydia do not have any symptoms so they may not even know they have it.

It is the most common bacterial STI world-wide, especially among people aged 15 to 29 years.

Chlamydia commonly infects the urethra, but can also occur in the throat, anus and even the eyes.

As the body’s immune system fights the STI, dead cells from the immune system, and cells that die as a result of the infection are occasionally passed out of the body as a clear or milky discharge or pus.

Other symptoms can be stinging pain or burning when urinating, or swollen and painful testes.

If left untreated, chlamydia can continue further into the reproductive system, affecting the seminal vesicles, vas deferens, epididymis and the testicles.

Because the vas deferens and the seminal vesicles are so small, any scarring as a result of the infection can contribute to reduced sperm counts and infertility.

Untreated chlamydia can also cause chronic epididymitis, which is persistent inflammation and pain in the testes that can be difficult to treat.

Chlamydia and other STIs can be prevented by using condoms and water-based lubricant during sex, having regular sexual health check ups and ensuring you or your health provider notify your sexual partners if you are diagnosed with an STI.

Symptoms in the rectum (bum)

  • Pain, bleeding or discharge

Symptoms in the throat

  • Usually causes no symptoms

Preventing chlamydia

  • Use condoms with water-based lubricant during vaginal and anal sex
  • Use condoms or dental dams during oral sex
  • Get tested for STIs every 6 to 12 months – the only way to know if you have an infection
  • If you've been diagnosed with chlamydia, avoid having sex with anyone until 7 days after you’ve finished your treatment.

Testing for chlamydia

Testing for chlamydia is easy. It involves collecting a urine sample or taking a vaginal swab. Sometimes you may also need to have a throat or anal swab.

If you don't have any symptoms, you can take your own swabs. But if you do have symptoms, the clinician will need to check you and take swabs themselves.

If you're over 16, live in Queensland and going to a health service is an issue, you can order a free chlamydia and gonorrhoea urine test online through 13 HEALTH Webtest.

Treating chlamydia

Chlamydia is easily treated with antibiotics.

It’s important to finish your treatment and follow up with your GP or health professional to make sure your infection is cured.

You should also avoid having sex for 7 days after finishing your treatment because you can still pass the infection on to other people during this time.

Book an STI test

Getting tested for STIs is a normal part of a healthy sex life. STI tests are quick, easy, confidential and often free.

Find a GP or local health service

Telling your sexual partners

If you have chlamydia, you should tell your current and past sexual partners so they can get tested and treated. This will also help stop you from getting it again. This is called contact tracing or partner notification.

Last updated: April 2024