This is because ovulation is relatively fixed in people with regular periods, and the ovulation day is 14 days before the next period. The chances of pregnancy are greatly increased during this period, while the rest of the time is called the safe period. The survival time of the egg after ovulation is 24 hours, if no conception occurs during this period, the egg will die on its own. 8 days before menstruation is a safe period and you will not get pregnant, but this is not absolute, some people have irregular menstruation and ovulation is not easy to determine, so there is no way to determine whether there is a possibility of pregnancy. If you do not have the requirement to have children, you should take good contraceptive measures whenever you have intercourse to avoid unwanted pregnancy.