The germ can be seen under ultrasound at 6 weeks of gestation, i.e., the germ and primitive heart tube pulsation can be seen in the uterine cavity when ultrasound examination is performed on day 42 of pregnancy. During the development of the fertilized egg the second week of pregnancy is called the gestational egg, after that the organs of the embryo gradually develop, forming the embryonic sac at 30-40 days after pregnancy, the germ at 40-50 days after pregnancy, and the fetal heart at 50-60 days after pregnancy, at which time the germ and the primitive heart tube beat can be seen under ultrasound. However, some pregnant women have irregular periods and the appearance of the germ may be earlier or later accordingly. Therefore, doctors generally recommend an ultrasound examination at 60 days after conception, when pregnancy can be confirmed and ectopic pregnancy can be ruled out, the gestational week can be estimated and serious fetal malformations can be detected. In conclusion, ultrasound is the preferred test to confirm pregnancy and to rule out other pathological conditions, so pregnant women should undergo pregnancy tests at the prescribed time during their pregnancy.