5 days before menstruation, can you get pregnant in the same room?

Generally, the first 5 days of menstruation belong to the safe period, there will be no egg discharge, so the probability of pregnancy is very low, but there is still a possibility of pregnancy, because some women's menstruation is irregular, ovulation time is uncertain, if there is sex life at this time and there is no contraceptive work to consider the possibility of pregnancy.