Pelvic inflammatory disease (PID) is an infection of the female reproductive organs caused by bacteria that spreads from the vagina or cervix. Common symptoms include abdominal pain and unusual discharge. Left untreated, PID can cause long-term complications like infertility, ectopic pregnancy, and chronic pelvic pain. PID is diagnosed based on symptoms and examination findings and treated with antibiotics. Prevention focuses on safer sex practices and STI screening/treatment to reduce risk of initial infection.