HCG, or human chorionic gonadotropin, is a glycoprotein secreted by the trophoblast cells of the placenta, which can be excreted into the urine through the blood circulation of pregnant women. Gynecological HCG examination is of significance in the diagnosis and treatment of early pregnancy, pregnancy-related diseases and tumors, and the common analyses are as follows: I. HCG positive, which can be seen in the following situations: 1. Pregnancy: HCG positive can be detected 10 days after conception HCG can be detected at 5 weeks after conception and can reach more than 2500U/L, with a peak at 9 weeks of gestation, reaching 100,000-200,000U/L; 2. Incomplete abortion: if there is still placental tissue remaining in the uterus, HCG will be characterized as positive; 3. Tumors: such as hyperemesis gravidarum, ovarian cysts, choriocarcinoma, gastric cancer, lung cancer, and colorectal cancer, etc., which can also cause HCG elevation. HCG negative, can be seen in the following situations: 1, no pregnancy: if there is no abnormal symptom manifestation, HCG test result is negative, then it is not conceived; 2, complete miscarriage or stillbirth: after pregnancy, HCG is below 2500U/L, and gradually decline, there is a possibility of miscarriage or stillbirth, when it drops to 600U/L, it is an inevitable miscarriage, and generally there is no need for fertility preservation treatment; 3, post-partum: after 4 days of production or After 13 days of abortion, HCG level in the body will gradually return to negative level.