Physiologic pelvic effusion refers to normal pelvic fluid, which mostly occurs after ovulation or early pregnancy in women, and can disappear naturally without treatment. Pelvic fluid can be observed through ultrasound. If the depth of the fluid is less than 3cm and there are no other uncomfortable symptoms, it usually doesn’t need to be treated; if it is slightly more than 3cm, it should be combined with the patient’s menstruation period, ovulation period, the presence or absence of abdominal pain and bloating, etc., in order to determine whether it is a pathologic pelvic effusion. During ovulation, menstruation or just after menstruation, there may be a slight increase in fluid, but if there is no other abnormality, there is no need to be concerned even if it is slightly more than 3cm.