Pelvic inflammatory disease (PID) is inflammation or infection of the uterus, fallopian tubes, or ovaries. It's usually caused by a bacterial infection, such as gonorrhea or chlamydia. If it isn't treated, PID can cause scar tissue in the pelvic organs and lead to infertility and other problems.
It may not cause any symptoms. But when it does, they may include pelvic pain, fever, and vaginal discharge.
After you've had PID, you are more likely to get it again.