Ovulation occurs about 14 days before menstruation and when ovulation is complete, the follicles will rupture and follicular fluid will be present in the pelvic cavity at this time. If there is no way to see the follicles during the ultrasound, only a certain amount of follicular fluid will be present in the pelvic cavity. If the follicles are still persistent, it is possible that they are not follicles but luteal cysts. It is recommended to go to the gynecology department 3 days after menstruation for a vaginal ultrasound to determine if there are any cysts. If there are persistent abnormal echogenicity, it is possible that pathological cysts may still be present. If it is small, it can be followed up and observed, but if it is large, it is recommended to perform laparoscopic exploration surgery to determine which area to operate on.