HCG is a glycoprotein secreted by placental trophoblast cells, which usually grows after a woman’s pregnancy and is important for early pregnancy diagnosis. Usually, the safe value of HCG varies depending on the stage of pregnancy. After a woman is pregnant, usually about 10 days after intercourse, HCG can be measured to rise and initially determine pregnancy, which belongs to 3-4 weeks of pregnancy, HCG value needs to reach 500-10000mIU/mL. 4-5 weeks of pregnancy HCG value needs to reach 1000-50000mIU/mL. 6-8 weeks of pregnancy UCG value needs to reach 15000- In the second and third trimesters of pregnancy, the value should reach 10,000-100,000 mIU/mL. By the end of the third trimester, the fetus is more stable and safe, and after a continuous period of peak, the serum HCG will gradually decrease. In early pregnancy, the patient needs to have an ultrasound. If the HCG is >10,000mIU/mL, the yolk sac can usually be seen in the uterine cavity, and it is safer if a fetal heartbeat is seen. Most spontaneous miscarriages occur before 12 weeks of pregnancy, so after 12 weeks, the fetus is more stable. If the patient has a history of miscarriage, weekly tests of serum HCG, progesterone and estradiol levels are recommended early in pregnancy. If there are abnormalities, they can be corrected in time for fetal preservation.