With the yolk sac, there are usually buds after 1-2 weeks, and the yolk sac can be seen by ultrasound around 6 weeks of pregnancy, and the buds can be seen around 7 weeks of pregnancy. The yolk sac is the earliest formation unit of blood vessels and blood cells in the embryo, and it is also the place of hematopoiesis. The normal development of the embryo depends on the production of the yolk sac, and then the fetal buds appear. With the yolk sac, there is usually a fetal bud after 1-2 weeks. If the patient has a yolk sac and has not seen a fetal heartbeat or buds for more than 2 weeks, then embryonic arrest is suspected to be more likely. Once the aforementioned manifestations occur, it is recommended to immediately seek medical attention, under the guidance of the doctor, improve the relevant examination, clarify the cause of the disease, and symptomatic treatment. It is recommended that pregnant women in the early stages of pregnancy should pay attention to regular checkups, more rest, healthy diet, do not be too tired, avoid coitus, relax, pregnant women with diseases should be actively treated to avoid affecting the development of the embryo.