The clinical distinction between the safe period and the ovulation period is made mainly because of the chances of a patient ovulating during these two periods. Women have the highest chance of ovulating during ovulation, and the chance of ovulating during the safe period is very low. So the main reason for projecting safe periods and ovulation is to help patients with contraception or to help them prepare for pregnancy. Women who are preparing for pregnancy should try to have intercourse during the ovulation period, which can greatly increase the chances of conception. Women who do not want to have children should try to have intercourse during the safe period, and if they have intercourse during the ovulation period, they should do a good job of contraception. Since female ovulation is affected by many factors, it is possible to ovulate during the safe period. Therefore, for women who do not want to have children, it is important to use contraception at all times, and to use contraception throughout the entire period.