Pelvic inflammatory disease (PID) comprises a spectrum of infections of the female upper reproductive tract. Most cases originate as lower genital tract infections that ascend to cause salpingitis, endometritis, myometritis, parametritis, tubo-ovarian abscess (TOA), perihepatitis, or focal pelvic peritonitis. Neisseria gonorrhea or Chlamydia trachomatis are common pathogens; however, 30% to 40% of infections are polymicrobial. Risk factors include multiple sexual partners, sexual abuse, adolescence, presence of other sexually transmitted diseases, douching, lack of condom use, delay in seeking care, and intrauterine device use. PID occurs less commonly in pregnancy, but first trimester infections can lead to fetal loss. Long-term sequelae include ectopic pregnancy, infertility, and chronic pain.