Blood values usually refer to blood HCG. Blood HCG may not appear to double around 8 weeks of pregnancy, which may be normal, or fetal arrest may occur. 1. Normal phenomenon: If the blood HCG does not double around 8-10 weeks of pregnancy, this situation may be normal. Because human chorionic gonadotropin is a glycoprotein hormone, it will reach its peak around 8-10 weeks of pregnancy, and will not be doubled, and there will be no fetal arrest. 2. Pathological factors: due to various reasons, such as intrauterine infection, chromosomal abnormalities, etc., may cause the embryo to stop developing, and there will be blood human chorionic gonadotropin does not double the situation. Therefore, if the pregnant woman appears 8 weeks pregnant blood HCG does not double the situation, it is recommended to consult a doctor in a timely manner, under the guidance of the doctor, improve the relevant examination, clarify the cause of the disease, symptomatic treatment.