Empty sac is not a case of waiting too long for an egg. Empty sac means that after the fertilized egg reaches the uterine cavity, it fails to settle and grow and develop, resulting in embryonic arrest. It may be due to poor quality of eggs and sperm, infection, immunogenetic factors, or poor endometrial environment, low levels of progesterone secreted by the ovaries, which do not allow the fertilized egg to continue to grow and develop, resulting in the cessation of the development of the situation. After the empty sac is determined to be unable to continue to grow and develop, it is necessary to terminate the pregnancy in a timely manner, otherwise it will lead to irregular vaginal bleeding and uterine cavity infection. Under normal circumstances, after the egg and sperm combine to develop into a fertilized egg, it will be transplanted to the uterine cavity in 7-8 days after sexual intercourse, and then grow and develop, and there will be a full gestational sac in the uterine cavity when the menopause is more than 40 days old and there will be fetal buds, which proves that it is not a vacuolar sac, and that the pregnancy can be continued.