Chlamydia is a common sexually transmitted disease (STD) that can cause infertility if untreated. Symptoms of chlamydia are rare and most people don’t know they have chlamydia so they don’t get tested.

Chlamydia is the most often reported bacterial STD in the United States. About 2.8 million Americans are infected annually. Women are often re-infected if their sex partners are not treated.

Chlamydia is passed person-to-person during vaginal, anal or oral sex.

Chlamydia can also be passed from an infected mother to her baby during vaginal delivery.

Anyone who has sex can get chlamydia. The more sex partners, the greater the risk of infection.

People at higher risk for infection include:

• Teenage girls
• Young women
• Men who have sex with men

If untreated, chlamydia can develop into serious reproductive and other health problems with both short-term and long-term effects. Like the disease itself, the damage is often “silent.”

For more information on the effects of untreated chlamydia, visit the Symptoms and Treatment webpage.

In pregnant women, there is evidence that untreated chlamydia can lead to premature delivery. Babies who are born to infected mothers can get chlamydia in their eyes and respiratory tracts. Chlamydia is a leading cause of early infant pneumonia and conjunctivitis (pink eye) in newborns.

There are laboratory tests to diagnose chlamydia. Some can be performed on urine; other tests require that a sample be collected from a site, such as the penis or cervix.

Chlamydia can be easily treated and cured with antibiotics. People with HIV and chlamydia should receive the same treatment as those who are HIV negative.

For more information on treating chlamydia, visit the Symptoms and Treatment webpage.

The best way to avoid the spread of STDs is to not have sex, or to have sex with only one partner who has been tested and is known to be uninfected. If used correctly every time, latex male condoms can reduce the risk of spreading of chlamydia.

For more information on preventing chlamydia, visit the Prevention webpage.