If the blood HCG does not increase but decreases after pregnancy, the main reason is that the embryo has stopped developing. Ultrasound examination is recommended to find out the size of the gestational sac and whether it corresponds to the number of days of menopause. In the vast majority of cases, the embryonic germ will be detected by ultrasound examination at about six weeks of pregnancy, and at about seven weeks of pregnancy, the primitive heart tube beat will be detected by ultrasound examination. If there is no germ or no primordial heartbeat at the appropriate gestational week, it is likely that the embryo has stopped developing. In combination with a decreased blood HCG test, it is recommended to terminate the pregnancy in time, otherwise there is a possibility of coagulation dysfunction, which may cause hemorrhage.