Women who have irregular periods and want to know if their follicles are developing normally and if they are ovulating normally can choose to go to the hospital for ultrasound follicle monitoring to confirm the diagnosis. For women with regular periods, they can go to the hospital on the 12th day of their menstrual cycle for the first follicular ultrasound monitoring. For women with irregular menstruation, they should go to the hospital on the 3rd day of their menstrual cycle. Ultrasound monitoring is one of the most intuitive methods of follicle monitoring, which can reveal the number, size and development of follicles in the ovaries. Generally, women with regular menstruation can go to the hospital to monitor their follicles on day 12 of their menstrual cycle, when the follicles are gradually developing and the dominant follicles are already obvious. If you see a dominant follicle on day 12, monitor it again every other day, because the dominant follicle grows faster, by 2-3 mm per day, so monitoring every other day can effectively see if the follicle is growing and developing normally. If the follicle has been discharged, it will not be visible under the ultrasound. If it is not discharged normally and continues to develop, then a luteal cyst will be formed. For women with irregular menstruation, ovulation will not be irregular, so they need to be monitored from the 3rd day of completely clean menstruation so that they can better grasp the follicle growth and expulsion.