Pelvic inflammatory disease (PID) refers to any inflammation of the female upper genital tract. It is usually caused by bacteria spreading from the vagina and cervix, commonly Chlamydia trachomatis or Neisseria gonorrhoeae. Left untreated, PID can lead to serious long-term complications like infertility, ectopic pregnancy, or chronic pelvic pain. Proper diagnosis is important so that antibiotics can be used to treat the infection and prevent permanent damage. Common symptoms include pelvic pain and abnormal vaginal bleeding or discharge.