hCG refers to human chorionic gonadotropin. When a woman becomes pregnant, hCG, which is originally present in the blood and urine, fluctuates as the number of weeks of pregnancy increases. Therefore, the hCG test is the earliest and most reliable method to determine whether a woman is pregnant or not. Common testing methods include the blood hCG test and the urine hCG test, which determines whether a woman has conceived by checking the presence of beta-subunit status in blood and urine. The blood hCG test can usually be done 8-10 days after intercourse. In normal pregnancy, the fertilized egg forms trophoblast cells and starts to secrete hCG a few days after its implantation. serum hCG titer gradually increases with the increase of pregnancy week, and the normal value of blood hCG is <10μg/L, and the normal value of β-hCG is <3.1μg/L. β-hCG is a part of hCG, and generally the β-hCG release in normal women The measured value is less than 3.1, if it is more than 5 then conception can be considered possible, if it is more than 10 basically pregnancy can be confirmed. 7-10 days of pregnancy: >5.0U/L; 30 days of pregnancy: >100U/L; 8-10 weeks of pregnancy: 50-100KU/L; 14 weeks of pregnancy: 10-20KU/L. From the above values, it can be seen that the peak is reached in 8-10 weeks of pregnancy and the serum hCG titer continues for 1-2 weeks and then gradually decreases. During the first 3 months of pregnancy, the level increases approximately double every 2.2 ± 0.5 days. Therefore, the doubling of the test can help indicate the state of pregnancy in the early stages of pregnancy. In addition to the above normal test, when the blood hCG is above 100000U/L and up to 1000000U/L and does not drop continuously, it can suggest the possibility of gravidity, but it is often difficult to distinguish from normal pregnancy when the blood β-hCG is at its peak, and then the diagnosis can be made according to dynamic changes or combined with ultrasonography.