The difference between fetal buds and primitive heart tube pulsation is that they represent different meanings and appear at different times. 1. Different meanings: Fetal buds are a kind of manifestation of the embryo development period in early pregnancy, generally between the 5th and 8th weeks of pregnancy is the period of fetal buds, and the embryo before the 8th week of pregnancy is called fetal buds. The primitive heart tube beat is the earliest fetal heart beat, indicating that the fetus has a heartbeat development and beat. 2. The time of appearance is different: the earliest fetal buds will appear in about 6 weeks of pregnancy, while the primitive heart tube beats appear a little later, usually in the fetal buds about 2~3mm long may see fetal heart beat, about 7~8 weeks of menopause have primitive heart tube beats. Early pregnancy through the examination of the fetal buds and primitive heart tube pulsation can determine whether the development of the fetus is normal or not, such as more than 8 weeks there is no fetal buds and primitive heart tube pulsation means that there may be fetal arrest, the need for timely diagnosis and termination of pregnancy.