An empty sac does not necessarily lead to a natural miscarriage. Miscarriages are classified into incomplete miscarriage, complete miscarriage, and missed miscarriage. Some people might experience abdominal pain and bleeding after the cessation of development in an empty sac, leading to a miscarriage. Others may retain the dead embryo in the uterine cavity, which is unable to be expelled in a timely manner, manifesting as the disappearance of early pregnancy symptoms, vaginal bleeding, or no symptoms at all, often being discovered during an examination. If the embryo has ceased development for a relatively long period, waiting for a natural miscarriage is not recommended. If the embryo is not expelled for a long time, there may be risks such as the embryo becoming tightly connected to the uterine wall, making dilation and curettage difficult. Additionally, there may be risks of coagulation dysfunction and disseminated intravascular coagulation.