Pelvic inflammatory disease (PID) is an infection of a woman's reproductive organs that is often caused by sexually transmitted infections like gonorrhea and chlamydia. In 2013, around 88,000 women were diagnosed with PID in the US. Left untreated, PID can cause problems becoming pregnant, complications during pregnancy, and long-term pelvic pain. Common symptoms of PID include lower abdominal pain, fever, foul-smelling discharge, painful sex, painful urination, and irregular periods. PID is usually treated with antibiotics, but untreated PID can lead to infertility, ectopic pregnancy, and chronic pelvic pain.