A woman’s period has just ended and it is not possible to get pregnant by having intercourse at this time because it is not the time of ovulation. To get pregnant, the sperm and egg need to meet in the female fallopian tube, form a fertilized egg and then swim back to the uterine cavity where it is planted. The egg usually survives 1-2 days in the body after it is expelled from the ovary, and the male sperm usually survives 4-5 days after it enters the female reproductive tract. Therefore, if a woman has a regular menstrual cycle, which is usually about 28-30 days, she can speculate when her next period will come. The day of ovulation is 14 days before the first day of blood from the next menstrual period, and within 4-5 days before and after the day of ovulation is the fertile period, and intercourse at this time is often easy to get pregnant, while intercourse at other times is not easy to get pregnant, which is the so-called safe period.