HCG, also known as human chorionic gonadotropin, is secreted by embryonic trophoblast cells after pregnancy, and the development of the embryo can be evaluated based on the value of HCG, but the exact time of fetal heartbeat cannot be inferred based on the specific value of HCG, because the value of HCG varies widely among different pregnant women and different weeks of pregnancy. The value of HCG varies greatly from pregnancy to pregnancy and from one week to another. According to the pattern of embryonic development, the fetal heartbeat and yolk sac can be monitored by ultrasound at around 6-7 weeks of pregnancy, and the HCG value is above 50,000 IU/L. If the value is low, it is possible that the fetal heartbeat may appear late or not at all, and the fetal heartbeat may appear at the latest by 8-10 weeks of pregnancy, otherwise it is considered that the embryo may have abnormal development.