Pelvic inflammatory isease (or disorder) (PID) is a generic term for inflammation of the female uterus, fallopian tubes, and/or ovaries as it progresses to scar formation with adhesions to nearby tissues and organs. This may lead to tissue necrosis with/or without abscess formation. Pus can be released into the peritoneum. Two thirds of patients with laparoscopic evidence of previous PID were not aware they had PID. PID is often associated with sexually transmitted diseases, as it is a common result of such infections. PID is a vague term and can refer to viral, fungal, parasitic, though most often bacterial infections. PID should be classified by affected organs, the stage of the infection, and the organism(s) causing it. Although an STD is often the cause, other routes are possible, including lymphatic, postpartum, postabortal (either miscarriage or abortion) or intrauterine device (IUD) related, and hematogenous spread.