Fertilized egg implantation may cause bleeding, but there are individual differences. Preparation for pregnancy women in the ovulation period after intercourse, fertilization will be completed 6 to 7 days after fertilization, some pregnant women in the bed during a small amount of vaginal bleeding, may also be accompanied by a slight pain in the lower abdomen, usually lasts for 3 to 4 days, it is a normal physiological phenomenon, do not need special treatment. However, not every pregnant woman will experience vaginal bleeding during implantation. The trophoblast cells start to secrete hCG (human chorionic gonadotropin) about 1 day after the fertilized egg has been laid, and blood hCG can be measured about 10 days after intercourse to confirm pregnancy, and ultrasonography can be performed about 40 days after menopause to make it clear that it is an intrauterine pregnancy. When paroxysmal abdominal pain accompanied by vaginal bleeding occurs during early pregnancy, you can go to the hospital to find out the cause and deal with it proactively.