If you have intercourse one day after your period clears or one day before your period, the chance of pregnancy is very small. Because if you usually have regular periods, your cycle is once every 28-30 days and ovulation occurs 14 days before your next period, so if you have intercourse before or after your period, your eggs will have died. Since the egg will die within 24 hours after ovulation if it is not fertilized, the chance of getting pregnant when having intercourse before or after your period is almost zero. It is recommended that in the case of regular menstruation, if you use the safety period contraception, the prerequisite is that your menstruation must be regular in order to use the safety period contraception, in order to achieve the purpose of contraception in clinical practice.