The reason why HCG does not rise may be caused by embryonic dysplasia, biochemical pregnancy, ectopic pregnancy and so on. 1. Embryonic dysplasia: If the embryo growth environment is not good, the mother has uterine fibroids, endometrial polyps, etc., or exposure to radioactive substances, then it is easy to affect the development of the embryo, or the embryo has genetic defects, there will be a situation that the HCG does not rise. 2. Biochemical pregnancy: If a woman has a biochemical pregnancy, because the fertilized egg has a shorter period of time, then HCG will not rise, accompanied by vaginal bleeding and other symptoms. 3. Ectopic pregnancy: If the gestational sac is not in the uterine cavity, then the gestational sac can not develop well, then HCG will not rise. If you find an abnormality during pregnancy, it is recommended that you consult a doctor in time to avoid delaying your condition.