Ultrasound can be used to monitor ovulation in patients who have been preparing for pregnancy for more than six months and still have not conceived, have irregular periods, and may have polycystic ovaries. Ultrasound is usually performed on the tenth day of menstruation (not ten days after cleansing), vaginal ultrasound is best (rectal ultrasound for non-sexual patients), to observe if there is follicular production. -If you see mature follicles (18-25mm in diameter) and the endometrial thickness reaches 8mm (preferably 10mm), you can use HCG 10000 units for intramuscular injection (of course, you can also not use the drug, the advantage of using the drug is to accurately grasp the ovulation time), 36 hours after using the drug The patient who has ovulated will have a small ovary and a small amount of fluid in the pelvis (mainly in the rectal fossa of the uterus).