The size of the gestational sac alone cannot determine whether it is an empty sac or not, and it should be judged in conjunction with other ultrasound manifestations, progesterone values and HCG values. Usually, if the gestational sac is 2-3cm, the ultrasound shows no yolk sac, fetal heart or buds, and the progesterone and HCG values have decreased, then the gestational sac is an empty sac. Empty sac indicates that the embryo is underdeveloped, and as the number of days of pregnancy increases, the embryo does not continue to develop without the presence of yolk sac, fetal buds, and primitive heart tube pulsation, and spontaneous abortion may occur. A common cause of empty sacs is chromosomal abnormalities in the embryo, which may be related to both sexes, such as maternal immune status, sperm quality, egg quality, intrauterine environment and other factors. Pregnant women with empty sacs have mild early pregnancy reactions, usually only mild nausea, may not have vomiting and anorexia and other early pregnancy reactions, occasionally have pain in the lower abdomen, may have irregular vaginal bleeding, usually a small amount of bloody discharge, coffee-colored discharge, or blood in the leukorrhea. If an empty sac is diagnosed, the doctor will usually advise the pregnant woman to terminate the pregnancy and perform a hysterectomy to remove the embryo from the uterine cavity in time. After the operation, bed rest for two weeks, keep warm and prevent cold, avoid contact with cold water and cold wind, and prohibit sexual intercourse.