Pelvic inflammatory disease (PID) affects the upper female genital tract, with infection causing endometritis, salpingitis, ovarian infections and pelvic peritonitis. The inflammation is caused by bacteria that take a retrograde route to the Fallopian tubes via the vagina and uterus, mainly secondary to intercourse. 

Salpingitis can be acute or chronic. In simple or acute catarrhal salpingitis the Fallopian tubes become red, swollen and secrete a greater amount of fluid. In most cases is caused by bacteria, the most common are: Chlamydia, Ureaplasma, gonococcal (causing gonorrhea), Mycoplasma, E. coli, Staphylococcus, and Streptococcus.