In general, women with regular menstruation can start testing on the 8th-10th day of their menstrual cycle and check every 2 days. In the case of irregular periods, more frequent monitoring is recommended. Follicle monitoring is often used clinically to guide patients to rapid conception. The follicles usually grow about 1-2mm per day and usually grow to about 2cm which is considered as mature follicles. Usually the doctor can recommend the next time to monitor ovulation based on the size of the follicle on the first ultrasound. Usually when the follicle is about to mature, women can be instructed to have intercourse to increase the chance of pregnancy. Ovulation test strips can also be used to monitor ovulation, but are less accurate than ultrasound ovulation monitoring. If you choose abdominal ultrasound for ovulation monitoring, you will need to hold your urine before the test; if you are having a negative ultrasound, you do not need to hold your urine.