"Pelvic inflammatory disease" is shorthand for any serious bacterial infection of the reproductive organs that are housed in the pelvis: the uterus, uterine lining, fallopian tubes, and/or ovaries. These infections usually start in the vagina and, when left untreated, can progressively infect other reproductive organs. 20% of PID cases are found in teens, who often are afraid or unable to get reproductive health care. PID can result in permanent infertility and chronic pain.