What is pelvic effusion? Pelvic effusion refers to the accumulation of a certain amount of fluid in the pelvic cavity, which can be caused by bilateral ovarian cysts, fallopian tube effusion, urinary tract infection, vaginal discharge, pelvic tumors or other diseases. Pelvic effusion can seriously affect women\’s reproductive health and therefore requires attention. Symptom 1: Back pain and lower abdominal pain One of the most common symptoms of pelvic effusion is lower abdominal pain, which may progress to back pain. Patients may experience sudden or gradual pain,