Ovulation is usually about 14 days before menstruation, if the menstrual cycle is very regular at 28-30 days, the period comes for a period of 7 days and ends at 8 days, counting from the first day of menstruation is the 15th day, which will just hover around the ovulation period. Therefore, it is possible to get pregnant. If you do not want to conceive, you can take oral emergency contraceptive pills to prevent pregnancy. For example, if you have your period for 3-5 days, even if it is the 8th day after the end of your period, it is still a relatively dangerous period and there is a chance of pregnancy. This is because the sperm remains in the vagina for about 48 hours, and it can take up to 3 days for the follicle to mature and rupture. If you still do not want to get pregnant, you should only take the emergency contraceptive pill. If you want to conceive during intercourse, you can buy a pregnancy test about 12 days after intercourse to rule out any pregnancy.