What is chlamydia?

Chlamydia is a bacterial sexually transmitted infection (STI). It can affect both males and females. Chlamydia can also cause a number of issues during pregnancy.

Chlamydia is the most commonly reported STI in Australia. But most people with chlamydia are not aware that they have the infection. Left untreated, chlamydia can cause serious complications including infertility and chronic pain. Chlamydia is usually easy to treat if you know you have it — one course of antibiotics is usually enough.

What are the symptoms of chlamydia?

Most people with chlamydia have no symptoms, which makes it very easy to spread. You can have the infection for many months or years without knowing it.

Females who have symptoms may have:

• vaginal discharge
• vaginal bleeding between periods or after sex
• burning or pain when urinating
• abdominal or pelvic pain
• pain during sex

Males who have symptoms may have some clear discharge from the penis or pain during urination.

In rare cases, people with chlamydia have sore joints (arthritis) or inflammation of the eye (uveitis).

How can chlamydia affect my pregnancy and my baby?

Chlamydia and your pregnancy

If you’re pregnant, it is especially important to diagnose and treat chlamydia, since it can cause serious complications. If you have chlamydia when you are pregnant, you have an increased risk of your waters breaking prematurely (premature rupture of membranes), causing the baby to be born early. Your health team will follow up closely, especially during the last trimester of your pregnancy.

Chlamydia and your baby

If you have chlamydia when giving birth, your baby might also become infected. Your baby’s doctor will check for eye infections (conjunctivitis) or pneumonia, and if your baby is infected, they might need antibiotics. Chlamydia has also been associated with low birth weight.

What causes chlamydia?

Chlamydia is caused by an infection with the bacterium chlamydia trachomatis. It is spread by unprotected sex (sex without using a condom) with an infected person, including vaginal, anal or oral sex.

If you are pregnant and you have chlamydia, your baby can be infected during birth.

When should I see my doctor?

You should see your doctor if:

• you have any of the symptoms of chlamydia
• you have had sex with someone who has chlamydia
• you have had unprotected sex (sex without using a condom)
• you are pregnant and think you may have chlamydia

FIND A HEALTH SERVICE — The Service Finder can help you find your nearest sexual health clinic or after-hours medical service.

How is chlamydia diagnosed?

Chlamydia is easily diagnosed. If you’re younger than 30 years, chlamydia tests are given routinely at your first antenatal visit. Your doctor may take a sample from your vagina (low vaginal swab), cervix, anus, penis or throat, and may ask for a first pass (‘first wee of the day’) urine test. During pregnancy, chlamydia is most often diagnosed with a urine sample or a vaginal swab you take yourself, rather than the doctor taking them.

Read more on how to take a vaginal swab yourself, or instruction for collecting a first pass (‘first wee’) urine sample.

The samples are sent to a laboratory for testing.

If you think you or your partner have chlamydia, see your doctor or sexual health clinic so you can both be tested. It is important that any sexual partners of people with chlamydia are tested, even if they don’t have symptoms.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

How is chlamydia treated?

Chlamydia is treated with a course of antibiotics. It is important for you to avoid having sex until you have finished the full course of treatment, and for at least a week following treatment. You should have another test for chlamydia 3 months after you are treated.

If you have chlamydia, all of your sexual partners should be informed. They should be tested and treated (if necessary), since they may be infected and can infect others, and infect you again, even after you have already been treated.

Your doctor can help you decide who may be at risk and help you to contact them either personally or anonymously. The website Let Them Know can also help to contact partners.

Chlamydia increases the possibility of contracting other infections. So it is important to be tested for other STIs such as gonorrhoea, hepatitis, HIV and syphilis.

The antibiotics used to treat chlamydia are safe in pregnancy and are used for many other types of infections.

How can chlamydia be prevented?

Using latex condoms can help you reduce your chance of preventing chlamydia and other STIs. Always use condoms with casual or new sexual partners.

Don’t have sex with people who are diagnosed with chlamydia until 7 days after they have completed their antibiotic treatment. If you are taking medicine for chlamydia but your sexual partner is not, you could be re-infected.

What are the complications of chlamydia?

If chlamydia isn't treated properly, it can cause serious complications. People who have chlamydia for long periods without treatment risk infertility.

In females, chlamydia can spread into the uterus and fallopian tubes, causing pelvic inflammatory disease. Pelvic inflammatory disease can lead to ectopic pregnancies, chronic pelvic pain and infertility.

In males, chlamydia can cause epididymitis (a painful infection near the testicle) or spread to the prostate gland, and the tubes that carry sperm. This may result in chronic pain and/or fertility problems.

Both males and females can develop sore joints (arthritis), inflammation of the eye (uveitis), or inflammation of the rectum.

If you have chlamydia when you are pregnant, you have an increased risk of your waters breaking prematurely (premature rupture of membranes), causing your baby to be born early.

If you have chlamydia when giving birth, your baby might also become infected. Complications for your baby may include low birth weight, eye infections and/or pneumonia.

Resources and support

You can also visit these websites for more information:

• Read more on the NSW Health chlamydia fact sheet.
• For information in other languages, visit the Stay STI Free website to download their chlamydia fact sheet.
• Better to know provides information about sexually transmissible infections for Aboriginal and/or Torres Strait Islander people.