The maximum value of HCG is related to the week of pregnancy. HCG starts to rise after pregnancy and reaches its peak in the eighth week of pregnancy and then gradually decreases. It remains at a relatively constant level until about 18-20 weeks, and reaches a maximum of about 200,000 mIU/ml by the 8th week of pregnancy. For pregnant women, early determination of HCG value can assess whether the embryo development is normal or not, and it can also be used to assist in the diagnosis of ectopic pregnancy, gravidity and other abnormal pregnancies, and it is also one of the screening indicators for Down’s syndrome in the middle of pregnancy. Since the HCG value varies greatly among different pregnant women in the same week of pregnancy, the early determination of HCG value cannot be judged as normal simply based on one monitoring result, but requires multiple tests to observe the doubling situation to determine whether the HCG is normal. If the HCG value is significantly higher or lower than the reference value, or if the doubling situation is not good, it is abnormal.