Chlamydia Trachomatis Symptoms, Causes, and Prevention

Chlamydia is the most common STI in Australia. Find out the symptoms, risks and how to prevent it.
1 min read
Chlamydia Trachomatis Symptoms, Causes, and Prevention


Quick facts about chlamydia:

  • Chlamydia is most common STI (sexually transmissible infection) in Australia
  • It easily transmitted from one person to another during sex without a condom, even if there are no symptoms
  • It affects anyone who is sexually active and particular for people who do not use condoms
  • If untreated, infection can eventually cause serious problems with the reproductive system
  • It is caused by the bacteria Chlamydia Trachomatis

Chlamydia is bacteria that can grow particularly in places where people have sex: vagina, urethra (urine passage), rectum (bum), or throat. Until it’s treated, it can live in these areas and can be passed on to other people, even without symptoms

Luckily, chlamydia can easily be cured with antibiotics.

People who are diagnosed with chlamydia most commonly are young women under the age of 30.


85-90% of people do not have symptoms.

If you do have symptoms, they can start anywhere from 2-14 days after sex.

Symptoms may include:

  • discharge (pus) from the penis, vagina, or rectum (bum)
  • painful urination: burning or stinging when peeing
  • sore balls (testes)
  • pain during sex
  • bleeding from the vagina after sex or between periods
  • bleeding from the rectum
  • pain when opening bowels or changes to the bowels
  • cramps or pain in the lower belly (pelvis)  in people with uteruses

When to see a doctor

If you have symptoms

If you have symptoms (see above) you should have a test. If the symptoms are severe, it’s important to be seen by a doctor or nurse who will assess if you need to have treatment right away.


People who are sexually active with casual partners should be tested for chlamydia every 3-6 months. This is called a screening test because the tests are done to make sure you’re not carrying chlamydia and don’t know it. 

If you are a sexual contact with someone with chlamydia

If you’re in contact with someone infected with chlamydia (someone who you’ve had sex with has tested positive for it), you should have a test to make sure you don’t have it too.

What is involved in testing

Tests involve a swab of the area that you collect yourself or a urine test. The tests are not painful.

What happens if I have chlamydia?

  • Your doctor or nurse will give you antibiotics that usually lasts for 1 week
  • Avoid sex while you’re taking the antibiotics 
  • Have a screening test 3 months after your antibiotics
  • Let people know that you’ve had sex for the last 6 months to go get a test
  • If you have symptoms, they will ease within a few days of treatment

Can I get reinfected with chlamydia?

Getting treated for chlamydia does not give you any future protection from getting chlamydia again.

Causes of chlamydia trachomatis

The Chlamydia trachomatis bacterium is most commonly spread through vaginal, oral and anal sex without condom. It's also possible for pregnant women to spread chlamydia to their children during delivery, causing pneumonia or a serious eye infection in the newborns.

Risk Factors

Factors that increase your risk of Chlamydia trachomatis include:

  • Being sexually active before age 25
  • Having multiple sex partners
  • Not using a condom consistently
  • History of sexually transmitted infection


If you have sex with casual partners, it’s important to get a screening test every 3-6 months. A screen will also include tests for other STIs.

When having sex with casual partners, using condoms will help reduce the risk of infections.

Try to avoid vaginal or rectal douching as this can expel the good bacteria and also damage the protective layer of the inside skin.


If chlamydia is not treated, it can cause some serious complications.

These can include:

  • Pelvic inflammatory disease (PID). PID is an infection in the uterus. This can cause you to feel very unwell, cause pelvic pain, and may need to be treated in the hospital if it is severe. PID can damage the reproductive tract and can lead to a higher risk of ectopic pregnancy (a pregnancy growing in the fallopian tubes) or infertility due to scarring.
  • Infection near the testicles (epididymo-orchitis). Chlamydia can cause  inflammation and infection of the small tubes in the back part of the testes. It can be quite painful, cause swelling, and lead to infertility.
  • Prostate gland infection. Rarely, chlamydia can infect the prostate gland, a component of male anatomy under the bladder. Prostatitis can cause pain during or after sex, fever and chills, painful urination, and lower back pain.
  • A pregnant person can pass gonorrhoea to their baby during birth causing complications for the baby
  • Ectopic pregnancy. This occurs when a fertilised egg implants and grows outside of the uterus, usually in a fallopian tube. The pregnancy needs to be removed to prevent life-threatening complications, such as a burst tube. A chlamydia infection increases this risk.
  • Infertility. Chlamydia infections — even those that produce no signs or symptoms — can cause scarring and obstruction in the fallopian tubes, which might make women infertile.
  • Reactive arthritis. Sometimes, a chlamydia infection can trigger an inflammatory condition called reactive arthritis, also called Reiter’s syndrome. This usually happens after the chlamydia infection has been cured. Reactive arthritis can affect the joints, the eyes, and your ability to urinate. 

Prevention of chlamydia trachomatis

The surest way to prevent chlamydia infection is to abstain from sexual activities. Short of that, you can:

  • Use condoms. Use a male latex condom or a female polyurethane condom during each sexual contact. Condoms used properly during every sexual encounter reduce but don't eliminate the risk of infection.
  • Limit your number of sex partners. Having multiple sex partners puts you at a high risk of contracting chlamydia and other sexually transmitted infections.
  • Get regular screenings. If you're sexually active, particularly if you have multiple partners, talk with your doctor about how often you should be screened for chlamydia and other sexually transmitted infections.
  • Avoid douching. Douching decreases the number of good bacteria in the vagina, which can increase the risk of infection.
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