Conditional analysis: For women with regular menstruation, you can calculate when the next menstruation will come, and subtract 14 days from the first day of the next menstruation. This day is ovulation day. If the woman's menstrual cycle is 28 days, her ovulation date should be about 14 days of the menstrual cycle; If the woman's menstrual cycle is 40 days, her ovulation date should be around the 26th day of the menstrual cycle (i.e. around 14 days before the next menstrual cycle). The date other than the dangerous period is the safe period. But the risk is small, and there is still the possibility of pregnancy.

Generally speaking, 3 days after menstruation is clean and 3 days before menstruation is an absolute safe period, so you will not get pregnant, and you will not get pregnant without any contraceptive measures. Don't worry, mainly because there is no ovulation at this time, and there is no condition for implantation in the uterus at this time.