A decrease in hCG value does not necessarily cause fetal abortion, but needs to be combined with the specific situation. hCG, human chorionic gonadotropin, is a glycoprotein hormone whose main functions are to increase the secretion of steroid hormones to maintain pregnancy, stimulate the production of luteinizing hormone, promote male fetal sexual differentiation, and stimulate thyroid activity. When a sexually mature female fertilized egg is laid and an embryo is formed, the placental syncytium trophoblast cells can produce a large amount of hCG, which is excreted in the form of urine through blood circulation. In normal early pregnancy (1~2.5 weeks of pregnancy), the hCG level in serum and urine can rise rapidly, reaching a peak at 8~10 weeks of pregnancy (15000~200000U/L), and gradually decreasing to a moderate level at 16 weeks of pregnancy, and remaining until the end of pregnancy. If the hCG level is lower than normal in early pregnancy, it is recommended to review it every other day, and if the value does not double, an abdominal ultrasound is needed to rule out ectopic pregnancy. If it is determined that intrauterine conception is normal, the decrease in value may be caused by delayed embryonic development, which may have reached its peak and needs to be evaluated under the guidance of an obstetrician and gynecologist. The decrease in hCG value should be combined with a gynecological examination to see the specific situation for observation and treatment.