The chances of pregnancy are relatively small when you have intercourse just after your period, but it does not mean that there is no possibility of pregnancy. Because ovulation does not usually occur just after menstruation, a woman’s ovulation date is usually about 14 days before her next menstrual period. After the egg is expelled from the ovary, it can survive in the fallopian tube for 1-2 days, waiting to be fertilized. Male sperm can remain viable in the female reproductive tract for 2-3 days, so it is easy to get pregnant in the days before and after the egg is expelled, which is also known as the ovulation period or fertile period, which is 5 days before and 4 days after the day of ovulation, together with the day of ovulation for a total of 10 days. In some women with short or irregular menstrual cycles, ovulation can occur early, or even near the end of menstruation, and the egg has the ability to be fertilized within 1-2 days, so if by chance male sperm enters, there is a good chance of conception. Therefore, women who do not intend to get pregnant at this stage are advised to take effective contraceptive measures. In addition, it is recommended that women avoid intercourse within 3 days of the end of their menstruation. At this time, intercourse, due to the contraction of the uterus during sexual impulse, can squeeze the endometrial fragments into the pelvic cavity, and the sperm meet with the endometrial breakage and the overflowing blood cells, or even enter the blood, which can induce the sperm to produce antibodies, thus triggering immune infertility.