Usually, for women with regular menstrual cycles between 21-28 days, the germ can be detected by gynecological ultrasound on the 41st day of pregnancy. For women with long intervals between menstrual cycles, it is not always possible to monitor the germ on day 41 of pregnancy, so it depends on the specific case whether the germ can be monitored on day 41 of pregnancy. For women with regular menstrual cycles, if the menstrual cycle is usually 21-28 days, it is possible to monitor not only the germ on day 49 of menopause, but also the primordial vascular pulsation. The gynecological ultrasound is the gold standard for determining whether the embryo is developing normally or not.