Without appropriate treatment, Chlamydia can spread to other parts of the body causing damage and serious long-term complications.

In women

Chlamydia can spread to other organs in the reproductive system causing pelvic inflammatory disease (PID). This can lead to complications such as pain in the lower abdomen, scarred or blocked fallopian tubes, infertility and ectopic pregnancy (pregnancy that occurs outside the womb).

In men

Chlamydia can lead to a painful infection in the testicles (balls), possible reduced fertility and an inflammation of the prostate gland in some men.

In men and women

Inflammation / swelling of the joints can occur. This might be accompanied by inflammation of the urethra (tube from the bladder to the outside of the body) and the eye (known as Reiter's syndrome). However, this is rare and more common in men than women.

A positive test result does not tell you how long someone has been infected. Some people get no symptoms at all or they can appear a long time after being exposed to chlamydia.

Chlamydia is a sexually transmitted infection. It can be caught by having vaginal, oral or anal sex; or sharing sex toys.

By always having safer sex - using condoms. Other contraceptives, such as using the coil, the pill or the implant etc, will only stop you getting pregnant; they won't stop you catching an infection.

Using a condom for all types of sex can greatly reduce the risk of picking up chlamydia and other sexually transmitted diseases.