Currently, ultrasound is the main method used to monitor ovulation, usually starting from the 8th day of the menstrual cycle, every 2 days when the follicle diameter is less than 16mm, once a day when the follicle reaches 16mm or above, and twice a day when the follicle is greater than 18mm. Currently, a more accurate and commonly used method to monitor ovulation is ultrasound, which is a transvaginal or abdominal ultrasound test to observe the growth, development and ovulation of follicles in a woman’s body. Generally, for women with regular menstruation, monitoring starts from the 8th day of the menstrual cycle, and when the diameter of the follicle is less than 10mm, it will be monitored every 3 days. When the diameter of the follicle is between 10~15mm, it should be monitored every 2 days; when the diameter of the follicle reaches 16mm, the monitoring should be changed to once a day; when the follicle is mature and the diameter reaches 18~22mm, it can be measured twice a day if necessary, until ovulation occurs. If women of childbearing age have the need to have children, they can monitor their follicles by ultrasound under the guidance of their doctors, and increase the number of coitus during the period of follicular maturity, which can effectively improve the chances of conception.