The facts:

  • Chlamydia is the most common STI in the UK and is a bacterial infection 
  • It often has no symptoms, especially in females so it may go undiscovered for years 
  • By the time it is discovered, it may have done irreversible damage to the reproductive system
  • Often the first a couple know of the presence of the infection is when they decide to start a family and have difficulty in conceiving
  • One in ten sexually active young people in the UK has chlamydia


This is a magnified picture of the bacteria that cause it.      

 Chlamydia bacteria

What causes chlamydia?

This STI is caused by a bacterium found in the semen and vaginal fluids of men and women who have the infection. 





How is it passed on?

  • Chlamydia is transmitted by having sex (vaginal, oral or anal) with an infected person
  • It can also be passed from an infected mother to her baby
  • It CANNOT be passed on by kissing, hugging, toilet seats or sharing a towel or cups/plates/cutlery with another person    


What are the symptoms (effects on our bodies)?

In 70% of cases there are no symptoms at all, which means a person can be infected with chlamydia without even knowing it.

If there are symptoms, they may be: 

in a woman:

  • abnormal vaginal discharge
  • burning or stinging when passing urine
  • pelvic pains or pain deep inside when having sex     

in a man:

  • burning or stinging when passing urine
  • milky white discharge from the penis
  • swelling and tenderness of the testicles (balls)


What is the treatment?

If picked up promptly, chlamydia can be very effectively treated with a course of antibiotics prescribed by the doctor.


What happens if untreated?

If left untreated, chlamydia can spread to other organs in the body. 

in a woman:

It can cause irreversible damage to the fallopian tubes with scarring leading to:

  • infertility - because of the scarring to the tubes a woman will have difficulty conceiving a child in later life
  • ectopic pregnancy - it may make her more likely to have an ectopic pregnancy (a pregnancy in the tube, not in the womb - this is a very serious medical emergency)
  • chronic pelvic pain - because of scarring of the tubes and other structures in the pelvis

in a man:

  • it can spread to the testicles causing pain and is linked to reduced fertility (difficulty conceiving a child) in later life


What to do if worried?

Any young person who has had unprotected sex (sex without a condom) with another person may be at risk.

If someone is concerned that they might have chlamydia they should speak to their GP (family doctor) or attend a local (genitourinary) sexual health clinic. 

The only way to be certain is to have a test. 

For help or advice see the section called TALK on the Students page. 

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