The best time to monitor ovulation is determined by the menstrual cycle, with monitoring starting on the 8th day after menstruation for short cycles and on the 10th-12th day after menstruation for long cycles. Ovulation is easy to calculate for women who have regular menstrual cycles, and is usually around the 14th day before the next menstrual period, with no difference of 2 days before or after, and the first 5 days and the last 4 days of this day are usually counted as the ovulation period. Everyone’s menstrual cycle is different, some are short and some are long. If you have a short cycle, you can start monitoring your ovulation with ultrasound on the 8th day after your period; if you have a long cycle, you can start monitoring on the 10th to 12th day after your period, and then you need to do ultrasound every day after the follicle is about 18mm. The chances of getting pregnant are greatest when you have intercourse during the ovulation period, so you need to arrange intercourse as soon as possible when ovulation is detected.