HCG is secreted by the cells of the syncytial trophectoderm, which is simply the part of the fertilized egg that will form the placenta in the future after division, and it is not part of the fetus. Therefore, the HCG level reflects the development status of the syncytial trophectoderm cells, and we often see cases where the HCG is 100,000 or more, but the pregnancy is still an empty sac. The HCG is not always rising, it starts to drop around 8 weeks, so it’s not that the fetus is bad if it drops. HCG doubling is the phenomenon that the HCG value doubles every 2-3 days. What about the other test “progesterone”? Here I will borrow a quote from Prof. Duan Tao. The reason for testing progesterone is that one of the major causes of miscarriage is luteal insufficiency (a small percentage), which leads to low progesterone levels and further leads to miscarriage. If detected in time, progesterone can be supplemented to prevent miscarriage from occurring. In fact, the gold standard for the diagnosis of luteal insufficiency is to perform two endometrial biopsies at mid-luteal phase, and it is almost impossible to use such a gold standard for diagnosis in clinical practice. This is why some people propose to check progesterone levels to determine luteal function, but this method is not reliable: 1, normal pregnancy progesterone levels fluctuate greatly (in fact, the same person may have a great difference between two tests on the same day); 2, low progesterone levels are more the result of embryonic dysplasia than the cause of miscarriage; 3, half of the patients diagnosed with luteal insufficiency have normal progesterone levels; 4, during early pregnancy, the source of progesterone is not normal. During early pregnancy, there are 2 sources of progesterone, one is secreted by the corpus luteum and the other is secreted by the trophoblast, so it is impossible to determine which cause of low levels is responsible. For these reasons, I do not advocate routine testing of HCG and progesterone, because such tests may seem wonderful, but they are powerless in terms of interpretation, prediction or intervention, and since the predictive value is limited and interventions are ineffective, sometimes Since such tests only add to the anxiety of the parents-to-be for nothing, I would not routinely test for them, and even if I did, it would never be for the purpose of guiding the use of medications for birth control. What are the circumstances in which I would check? In a pregnant woman with ovulation disorders, who does not know the exact time of ovulation and whose ultrasound does not reveal clinical evidence of pregnancy, I would choose to test for HCG to help determine the time of conception and progesterone to help determine the likelihood of ectopic pregnancy and miscarriage.