HCG doubling means that the HCG level in the blood of a pregnant woman increases in a multiplicative manner during pregnancy, especially in the early stages of pregnancy. If the HCG level does not double in the early stages of pregnancy, it does not exclude the possibility of preterm miscarriage or miscarriage, or ectopic pregnancy, but it also does not exclude the possibility that the embryo has stopped growing and developing. Therefore, the doubling of the blood HCG is important for understanding the early growth and development of the embryo. Once the patient has a significant drop in the value, he/she needs to go to the local public hospital for consultation and treatment and choose the appropriate fetal preservation treatment.