Normally ovulation occurs about 10 days after menstruation. Most women have a menstrual cycle of 28-30 days, with a period of 5-7 days, and about 10 days after menstruation, which is equivalent to about 16 days from the first day of menstruation, is the ovulation period or 14 days before the next period. If a woman has an irregular menstrual cycle, she can use ovulation test strips to detect a strong positive result or do a pelvic ultrasound for dynamic detection, and the follicles will be expelled when they reach about 2 cm in diameter. The date of ovulation is not fixed, and sometimes it is normal for ovulation to occur a few days earlier or later due to mental and psychological stress or work and environmental influences, and monitoring ovulation can not only guide conception, but also facilitate contraception.