Chlamydia is a bacterial sexually transmitted infection (STI) that affects both men and women. Chlamydia can also cause a number of issues during pregnancy.

Most people with chlamydia are unaware that they have the infection. Left untreated, chlamydia can cause serious complications including infertility and chronic pain. Chlamydia is fairly easy to treat if you know you have it — one course of antibiotics is usually enough.

Causes of chlamydia
Chlamydia is caused by an infection with the bacterium Chlamydia trachomatis. It is spread by unprotected (unsafe) vaginal or anal sex with an infected person.

What are the symptoms of chlamydia?
Most men and women with chlamydia have no signs or symptoms, which makes it very easy to spread. Some people have the infection for many months or years without knowing it.

Women who get symptoms may have:

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

Men who get 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).

Diagnosing chlamydia
Chlamydia is easily diagnosed. Your doctor may take a sample from the vagina, cervix, anus or penis, and may ask for a urine test. These 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.

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

If you have chlamydia, all of your sexual partners should be informed, tested and treated, as they may be infected and can infect you, and others, again after treatment.

If your partner has had a positive test for chlamydia, you should be treated even if you have had a negative test result. As chlamydia infection increases the possibility of contracting other infections, it is important to be tested for other STIs such as gonorrhoea, hepatitis, HIV and syphilis. Using latex condoms and a water-based lubricant is the most effective way to prevent STIs. People who have chlamydia for long periods without treatment risk becoming infertile or developing arthritis. Women can get pelvic inflammatory disease, and men can get epididymitis (a painful infection near the testicle).

Chlamydia complications
If chlamydia isn’t treated properly, it can cause serious complications. Both men and women can develop arthritis, eye inflammation and inflammation of the rectum. For women, chlamydia can spread into the uterus and fallopian tubes, causing pelvic inflammatory disease and infertility. In men, chlamydia can spread to the testes, the prostate gland, and the tubes that carry sperm, which may result in chronic pain and/or fertility problems.

Chlamydia and pregnancy
Women who have untreated chlamydia might develop pelvic inflammatory disease, which can cause ectopic pregnancies, chronic pelvic pain and infertility. Because of this, doctors recommend that pregnant women should be screened for chlamydia.

Pregnant women who are infected with chlamydia have an increased risk of their waters breaking prematurely, causing the baby to be born early.

If a woman has chlamydia when giving birth, the baby might become infected during delivery. These babies can develop an eye infection (conjunctivitis) or pneumonia, and might need antibiotics. Chlamydia has also been associated with low birthweight.

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