Women suffering from pelvic effusion may have some relationship with men, but it does not mean that pelvic effusion must be caused by sex. The causes of pelvic effusion mainly include physiological factors, sex life, pelvic tumors and so on. 1. Physiological factors: usually a small amount of pelvic fluid may appear before or after the female physiological period or during ovulation, which is a normal physiological phenomenon and can be left untreated if it does not affect the patient’s normal life. 2. Sexual life: if both men and women do not pay attention to personal hygiene during sexual life, there may be bacterial infection. If the infection spreads to the pelvis, there may be inflammatory exudate in the pelvis, thus pelvic effusion occurs. 3. Pelvic tumor: when the pelvic tumor progresses to a certain size, pelvic effusion may occur, and the amount of effusion is closely related to the severity of the disease. Patients need to go to the hospital and follow the doctor’s instruction to improve the relevant examination and treatment.