It depends on the time of ovulation. If the fertilized egg is formed right after intercourse, it usually appears 7-9 days after intercourse. A woman only expels one mature egg per month, and if the egg meets the sperm in the fallopian tube within 24 hours of expulsion. The sperm and egg unite to form a fertilized egg, which moves from the fallopian tube to the uterine cavity and after 6-8 days can reach the uterine cavity where it implants in the endometrium and gradually develops into a mature fetus by absorbing nutrients. Therefore, if the fertilized egg is formed right after intercourse, the implantation usually occurs 7-9 days after intercourse, but the sperm can survive in the woman’s body for 3-5 days at most, and the time of implantation and fertilization should be calculated in conjunction with the time of ovulation. In addition, a few women may experience a small amount of vaginal bleeding at the time of fertilization, which usually lasts for 2-3 days and can be relieved on its own without treatment.