Reviewed June 2019

How can I tell if I have chlamydia?

how can i tell if i have chlamydia 1200400

Chlamydia is a common infection caused by the bacteria Chlamydia trachomatis. It is spread by having unprotected sex (sex without a condom) or contact with infected genital fluid such as semen. Chlamydia can also be passed from one woman to another via contact of genital fluid. The bacteria is carried via the genital fluids and once passed from one person to the next, the bacteria infects and lives in human cells leading to genital infections, pneumonia, and eye infections.

However, chlamydia cannot be transmitted by kissing, swimming pools, sharing towels, or toilet seats. It may be passed from an infected pregnant woman to her baby because the bacteria can pass through the placenta from the mother to the baby. In the UK it is one of the most common sexually transmitted diseases, particularly among sexually active young people.1

What are the symptoms of chlamydia?

It may be difficult to actually know if you have contracted chlamydia because most people do not have any symptoms at all. The suspicion may only be raised if there has been a known contact with chlamydia or from testing after unprotected sex. It is important that you get tested if you suspect you have chlamydia because there are treatments available and if left untreated it can have serious short term and long term effects.

In the short term after infection, some women may experience unusual vaginal or rectal discharge,2 which is described as yellow or milky white. This is because the chlamydia bacteria infects the cells in the vagina and rectum stimulating mucous secretion, and these secretions (produced by the mucous glands) combine with dead infected cells to produce discharge.

A white discharge may also be caused by vaginal thrush, however, but this is usually curd-like, often odourless, or smells like bread or yeast. It is also often associated with vaginal itching or redness.

A green, rather than yellow discharge, along with a foul smelling odour, may be due to other sexually transmitted diseases such as trichomoniasis.3 A grey-white watery vaginal discharge that has a strong fishy smell may be due to bacterial vaginosis, which is caused by a disruption of the balance of normal vaginal bacteria.4 So, the difference in colour and smell of the vaginal discharge may differentiate between whether it is likely to be caused by chlamydia or not.

A burning sensation or pain on peeing as well as urgency to pass urine may also occur with chlamydia infection. This is because the chlamydia infects the urethra (tube from bladder to vaginal opening) causing urinary tract infection.5 However, chlamydia is only one cause of a urinary tract infection and there are other bacteria such as E.coli can also cause urinary infections.

There is no way to tell if chlamydia is the cause of your UTI unless there is a urine sample test or other accompanying symptoms such as abnormal genital discharge. If you are getting treated for a UTI and you believe you may have been exposed to chlamydia, it is important to go and get tested for chlamydia, too. This is because the antibiotics prescribed to treat your UTI may not be the correct ones to treat chlamydia.

Chlamydia may also cause pain during sexual intercourse because the chlamydia infects the cervix which, when stimulated by sex, causes pain. Similarly, there may be bleeding between periods or after intercourse,6 because the inflammation of the infected cervix makes the blood vessels on the cervix more likely to bleed. There are other causes of painful intercourse or bleeding between periods or after intercourse such as endometriosis and fibroids. However, these conditions, in general, are not associated with abnormal vaginal discharge.

What happens if chlamydia is untreated?

In the long term, if chlamydia is untreated, the infection may spread across the reproductive system and other organs. Inflammation of the cervix causes odorous vaginal discharge, abnormal bleeding, and pain during intercourse. With more widespread infection involving the Fallopian tubes (the tubes leading from the ovaries to the womb) and uterus, a condition called pelvic inflammatory disease (PID) can develop.7

The chlamydia bacteria infects the Fallopian tubes causing swelling and scarring of the tissues. This leads to blockage, and prevents the movement of eggs into the uterus. For this reason, fertilisation becomes a problem, and chlamydia can be responsible for causing infertility.8 Other sexually transmitted diseases, such as gonorrhoea, may also cause PID in the same way.

Scarring of the Fallopian tubes can increase the chance of ectopic pregnancy, where the fertilised egg implants somewhere other than the uterus, for example in the Fallopian tubes. When this occurs, the embryo begins to grow and the tubes can rupture, leading to sudden onset of severe pain and bleeding. This can be life threatening if the embryo is not surgically removed. Therefore, it is important to seek immediate medical attention if you have sudden severe tummy pain with a positive pregnancy test.

Chlamydia can be passed from pregnant women to their unborn child. As such, it is associated with pre-term births, infant eye infections (conjunctivitis), and lung infections (pneumonia). For this reason, it is important to receive treatment for chlamydia early.

Treatment for chlamydia

Chlamydia is treatable with antibiotics (such as azithromycin or doxycycline) if given early. Because the most common symptom is no symptoms at all, it is important to seek medical advice from your GP or sexual health clinic and be tested if you sleep with a new partner without using condoms. Testing can be very easily done by taking a urine sample or genital swab. If you are infected with chlamydia it is recommended that sexual partners should also be tested.

Last updated June 2019
Next update due 2021

Dr. Diana Chiu, MBChB (Hons) MRCP PGCERT (Med Ed) PhD

Diana received her medical degree, with honours, from the University of Manchester. She then went on to receive basic and specialist medical training within the north west of England. She carried out in-depth research in medicine and was awarded a PhD in 2016. Currently, she is finishing her medical training at a large teaching hospital, and one of her greatest interests is medical education. She is an advanced life support instructor and writes regularly for post-graduate examination websites, and also holds a PGCERT in medical education with distinction.

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  1. Adams, E.J., et al., Chlamydia trachomatis in the United Kingdom: a systematic review and analysis of prevalence studies, Sexually Transmitted Infections, 2004, vol 80, pp 354-362
  2. O’Connell, C.M., and Ferone, M.E., Chlamydia trachomatis genital infections, Microbial cell, September 2016, vol 3, issue 9, pp 390-403
  3. NHS, Trichomoniasis: Overview, [website], (accessed 28 June 2019)
  4. Livengood, C.H., Bacterial vaginosis: an overview for 2009, Obstetrics & Gynecology, Winter 2009, vol 2, issue 1, pp 28-37
  5. O’Connell, C.M., and Ferone, M.E., Chlamydia trachomatis genital infections, Microbial cell, September 2016, vol 3, issue 9, pp 390-403
  6. Ibid
  7. Haggerty, C.L., et al., Risk of sequelae after Chlamydia trachomatis genital infection in women, The Journal of Infectious Diseases, June 2010, vol 201, issue supplement 2, pp 134-155
  8. Ibid

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