Women with pelvic effusion are considered to be related to physiological effusion formed during menstruation and ovulation and pathological effusion caused by pelvic inflammation and digestive system diseases. 1. Physiological fluid: due to menstruation and ovulation, changes in estrogen and progesterone levels in women’s bodies or the discharge of follicles, physiological fluid may form in the pelvic cavity, which can be gradually absorbed on its own. 2. Pathologic effusion: (1) Pelvic inflammatory disease: If a woman has pelvic inflammatory disease, pelvic fluid may be formed due to the increase of inflammatory exudate and the congestion and edema of pelvic organs or connective tissues. (2) Digestive system diseases: such as chronic diarrhea, appendicitis and other diseases, may lead to increased tissue exudate, and at the same time, due to the pelvic cavity and the abdominal cavity are connected, pelvic effusion may be formed. There are more reasons for women to have pelvic effusion, it is recommended that patients seek timely medical treatment, improve the relevant examination, clarify the cause of the disease and then actively treat under the guidance of the doctor.