At 5 days after intercourse, the fertilization of the egg is not completed. Because the sperm enters the woman’s fallopian tube 20-240 minutes after sexual intercourse, and after the sperm unites with the egg, the fertilized egg will undergo cell differentiation in the fallopian tube, so it does not necessarily enter the woman’s uterus immediately after fertilization. At this point, the embryo begins to move gradually into the uterus and continues to differentiate as it does so. Therefore, it takes 6-8 days from the time of intercourse until the fertilized egg enters the uterine cavity of the woman, so even if fertilization is complete at this time, pregnancy cannot be detected because the human chorionic gonadotropin in the body has not yet begun to change significantly.