The diagnosis of fetal arrest is not necessarily followed by abdominal pain and bleeding immediately. In some pregnant women, the embryo does not continue to differentiate and develop during the development process, and the fetal buds and primitive heart tube pulsations do not appear on schedule, and the diagnosis is based on the number of days of menopause combined with HCG and ultrasound. However, some of the trophoblast cells in the embryo will continue to grow and develop into an empty gestational sac without abdominal pain and vaginal bleeding. After embryonic abortion, the embryo is completely dead and the HCG level in the body drops, uterine contractions, abdominal pain and a small amount of vaginal bleeding will occur. A comprehensive judgment will be made after embryonic abortion based on clinical symptoms and a complementary test.