If menstruation is usually regular and the cycle is once every 28-30 days, in the vast majority of cases, a gestational sac can be seen in the uterus by ultrasound examination at about 35 days of menopause, and at about 40 days of menopause, the yolk sac can be seen inside the gestational sac by ultrasound examination. At more than 6 weeks of menopause, the germinal tissue can be seen by ultrasound. In addition, if the primordial ventricular pulsation can be seen by ultrasound examination at about 7 weeks of menopause, these are a few important indicators of early pregnancy. If the embryonic tissue is not visible at the corresponding week of pregnancy, it is likely to be caused by dysplasia, for example, if the yolk sac is not visible at 7 weeks of pregnancy, clinically it is likely to be an empty sac, and it is recommended to terminate the pregnancy in time with the medical history and with the blood HCG and progesterone tests.