The vast majority of pregnant women do not bleed during the process of embryo implantation. Only a small number of pregnant women have a small number of broken capillaries during the process of implantation, which can cause bleeding during implantation, and no bleeding during implantation is normal. The process of implantation requires three processes: positioning, adhesion, and invasion. After implantation, the embryo has to develop rapidly in the endometrium. If most of the embryos are well developed and have sufficient luteal and estrogen support, they will quickly form a yolk sac, a fetal heart and a germ. If the embryo is not well developed or if the endometrial environment is not good, or if the corpus luteum is not functioning properly, it can lead to miscarriage in early pregnancy, which is often referred to as biochemical pregnancy or spontaneous abortion. The sensitivity of the embryo to the external environment increases significantly after implantation, and medication should be used carefully in early pregnancy to avoid adverse effects on the fetus.