What is chlamydia?
Chlamydial infection is the most frequently reported STI in the U.S. If left untreated, chlamydia can cause pelvic inflammatory disease (PID), ectopic pregnancy, infertility, and chronic pelvic pain due to scarring of fallopian tubes and other tissues inside of the pelvis and upper abdomen. You can get chlamydia by having vaginal, anal, or oral sex with someone who has chlamydia.