Chlamydia is the most frequently reported bacterial STD in the United States

Causes and Symptoms

Chlamydia can be transmitted during vaginal, anal, or oral sex. An estimated 2.8 million Americans are infected with chlamydia each year. Three-quarters of infected women and half of infected men have no symptoms.

Women are frequently re-infected if their sex partners are not treated.

Sexually active girls and young women are especially susceptible to chlamydia because the cells that form the lining of the immature cervix are easily invaded by the bacteria.

Chlamydia is known as a “silent” disease because the majority of infected people have no symptoms. If symptoms do occur, they usually appear within 1 to 3 weeks after exposure.

Women with symptoms might have an abnormal vaginal discharge or a burning sensation when urinating. When the infection spreads from the cervix to the fallopian tubes, some women still have no symptoms; others have lower abdominal pain, lower back pain, nausea, fever, pain during intercourse, and bleeding between menstrual periods.

Men with signs or symptoms might have a discharge from their penis or a burning sensation when urinating. Men might also have burning or itching around the opening of the penis.

Whenever the infection spreads past the cervix, permanent and irreversible damage can occur to the fallopian tubes, uterus, and tissues surrounding the ovaries. This damage can lead to chronic pelvic pain, infertility, and potentially fatal ectopic pregnancy.


Widely available laboratory tests can accurately detect chlamydia bacteria in a urine sample, or by collecting swab specimens from endocervix, vagina or penis.


Chlamydia can be treated and cured with antibiotics.


How can chlamydia be prevented?

The surest way to avoid transmission of STDs is to abstain from sexual contact, or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected.

Latex male condoms, when used consistently and correctly, can reduce the risk of transmission of chlamydia.

CDC recommends yearly chlamydia testing of all sexually active women age 25 or younger, older women with risk factors for chlamydia infections (those who have a new sex partner or multiple sex partners), and all pregnant women. An appropriate sexual risk assessment by a health care provider should always be conducted and may indicate more frequent screening for some women.

Any genital symptoms such as an unusual sore, discharge with odor, burning during urination, or bleeding between menstrual cycles could mean an STD infection. If a woman or man has any of these symptoms, they should stop having sex and consult a health care provider immediately.

Treating STDs early in women can prevent PID. Women and men who are told they have an STD and are treated for it should notify all of their recent sex partners (sex partners within the preceding 60 days) so they can see a health care provider and be evaluated for STDs.

Sexual activity should not resume until all sex partners have been examined and, if necessary, treated.


Centers for Disease Control and Prevention (Aug 17, 2011).

Stamm, W. E. (1999). “Chlamydia trachomatis Infections of the Adult.” In Sexually Transmitted Diseases, 3rd edition, eds. K. Holmes, P. Mardh, P. Sparling et al. New York: McGraw-Hill.