Pelvic inflammatory disease (PID) is an infection of the female reproductive organs, including the uterus, fallopian tubes, and ovaries. It often occurs when sexually transmitted infections, such as chlamydia or gonorrhea, spread from the vagina to the upper reproductive tract. Symptoms may include pelvic pain, fever, and unusual discharge. If left untreated, PID can lead to serious complications, such as infertility or chronic pelvic pain. Diagnosis typically involves a physical examination, lab tests, and imaging studies. Treatment usually includes antibiotics to eliminate the infection and may require hospitalization in severe cases.