The time to test the follicles should be calculated according to the usual time of menstruation, which means that it is related to the menstrual cycle. If you have a 28-day period, follicle monitoring should start on the 10th day of your period. After the 10th day of menstruation, the follicles start to develop, so the test should start on the 10th day and then the next test should be scheduled according to the size of the follicles. If your period is abnormal or your menstrual cycle is irregular, you should start measuring from the 8th day of your period, especially if your menstrual cycle is short, if it is 24-25 days once, you should ovulate on the 10th day, and you should test on the 8th day of your period at this time. Therefore, the time to test the follicles should be based on the menstrual cycle.