After in vitro transfer, embryos will wander around the uterine cavity for 2-3 days and start to bed in 3-5 days. Some patients will have a small amount of bleeding or pain during bedtime, which are all normal. After 3-5 days of in vitro transfer, some patients will have slight abdominal pain, backache, fatigue, a small amount of vaginal bleeding and breast tenderness when the embryo is in bed, all of which are normal after implantation. If the patient does not feel anything, it does not mean that the embryo has not come to bed. Therefore, the blood test is the main criterion to determine whether the embryo has come to bed. After the embryo has been implanted, the trophoblast cells start to secrete chorionic gonadotropin, or HCG, which can be detected in the blood as early as 3-4 days after implantation, but the amount is very small. HCG can be detected in the blood as early as 3-4 days after implantation, but the amount is very small. 9-10 days after implantation, HCG can be detected in the blood, which means the embryo is successfully implanted. In daily life, women preparing for pregnancy should have a balanced diet with more vitamin and protein-rich foods and also take folic acid tablets in the first trimester of pregnancy to prevent neural tube abnormalities.