Chlamydia is very common—nearly three million infections in the U.S. each year.  It is estimated that 1 in 20 sexually active young women aged 14-24 years has chlamydia.

Chlamydia is often a “silent” infection: about 75% of women and 50% of men don’t have symptoms and don’t know they are infected. And undetected, untreated chlamydia can lead to serious health problems. For example, untreated chlamydia infections in women may lead to pelvic inflammatory disease (PID), a serious infection of a woman’s reproductive organs, which in turn can cause infertility. Chlamydia also can cause a potentially fatal ectopic pregnancy (pregnancy that occurs outside the womb).

Learn more about chlamydia, how it is transmitted, and how you can prevent infection.