Fertilized egg implantation bleeding mainly occurs about 7-10 days after ovulation, if a woman is sure that she has conceived after intercourse, it takes about 7 days for the fertilized egg to implant. If a small amount of bleeding occurs during this period, and the embryo develops normally, it should be considered as implantation bleeding, which is mostly caused by fluctuating hormone levels after the fertilized egg is implanted. If there is no ovulation before or at the time of intercourse, the sperm can survive in the woman’s body for 72 hours, and there is a possibility of conception if ovulation occurs within 3 days after intercourse. So at the latest 10 days after intercourse the fertilized egg will be able to implant, so the implantation bleeding occurs at the latest about 10 days after intercourse. Bleeding on fertilization is very unlikely to occur in most cases, and patients with bleeding on fertilization have a relatively high chance of having a biochemical pregnancy or an embryo that stops developing.