Chlamydia in Women and Men

Chlamydia in Women and Men screen, an optional test only depending on clinical risk

Chlamydia is the most common sexually transmitted infection in Ireland. It often causes no symptoms, and can be passed on to others without you realising. However, symptoms and complications may develop if it is left untreated. A short course of an antibiotic clears the infection in most cases.

What is chlamydia?

Chlamydia is an infection caused by a bacterium (germ) called Chlamydia trachomatis. In women, chlamydial infection usually affects the cervix and uterus (the womb). In men, it usually affects the urethra in the penis.

How do you get chlamydia and how common is it?

Most people with chlamydia got the infection by having sex with an infected person. About 1 in 20 sexually active women in Ireland are infected with chlamydia. It is most common in women under 25. (About 1 in 12 women aged 20 are infected with chlamydia.) The number of cases has risen sharply in recent years. Many women are not aware that they are infected as it often causes no symptoms. You can be infected with chlamydia for months, even years, without realising it.

The risk of infection increases with the number of changes of sexual partner. Wearing a condom during sex helps to prevent chlamydia and other sexually transmitted infections.

What are the common symptoms of chlamydia?

No symptoms occur in up to 8 in 10 cases. If symptoms do occur, they can include:

  • Vaginal discharge. This is due to the cervix becoming inflamed.
  • Pain or burning when you pass urine.
  • Bleeding or spotting between periods. In particular, bleeding after you have sex.
  • Pain or discomfort in the lower abdomen (pelvic area), especially when you have sex.

Why should I have treatment if I have no symptoms?

  • Because the infection may spread and cause serious complications (see below). This can be months or years after you are first infected.
  • You can pass on the infection to your sexual partner(s) even if you do not have symptoms.

Do I need any tests?

Chlamydia can be confirmed by a ‘swab’ taken from the cervix and urethra. (A swab is a small ball of cotton wool on the end of a stick which is used to obtain mucus and cells to send to the lab for testing.) Newer tests using a urine sample or a swab from the lower vagina are becoming increasingly used. You may also be advised to be tested for other sexually transmitted infections.

What is the treatment for chlamydia?

A short course of an antibiotic usually clears chlamydial infection. Even if you have no symptoms, treatment is strongly advised to prevent possible complications. Tell your doctor if you are (or may be) pregnant. This may affect the choice of antibiotic. Do not have sex until you and your sexual partner have finished treatment (or for seven days after treatment with a ‘single dose’ antibiotic which is sometimes used).

Does my partner need to be treated?

Yes. Also, any other sexual partners within the past six months should also be tested for infection. (If you have not had sex within the last six months then your latest sexual partner should be tested and treated, however long ago the relationship was.) A course of an antibiotic is usually advised whether or not infection is found on testing. This is because:

  • Chlamydial infection is commonly passed on during sex.
  • Men and women often have no symptoms with chlamydia, but can still pass on the infection.
  • The test for chlamydia is not 100% reliable. Treatment makes sure that any possible infection which may have been missed by the tests is cleared.
  • If your sexual partner is infected and not treated, chlamydia can be passed back to you again after you are treated.

What are the possible complications of chlamydia?

  • If left untreated, the infection may seriously affect the uterus and fallopian tubes (called ‘pelvic inflammatory disease’ or PID). About 1 in 5 women with chlamydia develop PID. This may develop suddenly and cause fever and pain. It can also develop slowly over months or years without causing symptoms (also known as ‘silent PID’). However, over time, scarring or damage to the fallopian tubes may occur and can cause:
    • Chronic (persistent) pain.
    • Difficulty becoming pregnant (infertility).
    • If you become pregnant, you have an increased risk of ectopic pregnancy (where the pregnancy develops in a fallopian tube and can cause serious life-threatening problems). About 4 in 10 ectopic pregnancies are due to infection with chlamydia.
  • The risk of developing some complications of pregnancy such as miscarriage, premature birth, and stillbirth are increased in pregnant women with untreated chlamydia.
  • If you have untreated chlamydia during childbirth, your baby may develop a chlamydial infection of their eye or lung during the birth.
  • Reiter’s syndrome is a rare complication. This causes arthritis and eye inflammation. It may be due to the immune system ‘over-reacting’ to chlamydial infection in some cases.

The risk of complications is much reduced if chlamydial infection is treated early.

What causes non-gonococcal urethritis?

  • Infection with chlamydia causes about half of cases of NGU. Chlamydia is a bacterium (germ) that is usually caught by sexual contact with an infected person. You can pass chlamydia on during vaginal, anal or oral sex.
  • Various other bacteria or viruses which are sexually transmitted can cause NGU.
  • A non-infective problem is, rarely, the cause. For example, injury or surgery to the urethra can cause inflammation.
  • No cause can be found in about 1 in 4 cases. Sexually transmitted infections that are not identified by tests are probably the cause of some of these, but not all. However, it is not possible to say which of these cases are due to infection and which are not.

What are the symptoms of non-gonococcal urethritis?

  • A white discharge (fluid) from the end of the penis is common, but does not occur in every case.
  • Pain or burning when you pass urine. This may be confused with a urine infection.
  • Irritation inside the penis.
  • A feeling of wanting to pass urine frequently.
  • In a small number of cases the infection travels up the urethra to the testes and causes pain and swelling in one or both testes.
  • A rare complication is a type of arthritis which can be triggered by NGU. It may be due to the immune system ‘over-reacting’ to some bacteria that can cause NGU.
  • Up to half of men with chlamydia infection (the most common cause of NGU) do not have any symptoms.

The symptoms may clear over time, even without treatment. This may take up to six months, but can be just a couple of weeks or so. However, without treatment, bacteria that cause NGU often remain in the urethra. It is just that the symptoms may go.

Therefore, even if symptoms go, there is a good chance that you can pass on the infection if you are not treated.

A specimen of the discharge (a ‘swab’), and/or a urine specimen, may be taken to try and identify the cause of the infection. You may also be advised to have tests for other sexually transmitted infections.

What is the treatment for non-gonococcal urethritis?

A short course of antibiotics usually clears NGU. The antibiotic prescribed may depend on which bacteria are found (often chlamydia), and whether other infections are also present.

If no bacteria are found by the tests, you may still be advised to take a course of antibiotics if you have symptoms of NGU. Infection is still the likely cause, even if a bacterium cannot be identified.

Most people get better with antibiotic treatment.


A doctor or health care professional will often want to know that treatment has worked. It is common to be reviewed a couple of weeks after you start treatment to check that symptoms have gone. Sometimes re-testing and a second antibiotic is needed if symptoms persist.

You should not have sex until both you and your sexual partner(s) have finished treatment.