The absence of a gestational sac in the uterine cavity means that there is no pregnancy, or that the gestational sac is deposited outside the body cavity of the uterus, possibly in the case of ectopic pregnancy, but there is no gestational sac in the uterine cavity, the site of deposition of the gestational sac is not in the uterine cavity, or possibly in the case of a biochemical pregnancy, no gestational sac is found outside the uterine cavity either. There is also a case of delayed ovulation and late formation of the fertilized egg and late implantation of the fertilized egg in the uterine cavity. If the chorionic gonadotropin is greater than the reference value, a gynecological ultrasound can be done at least 40 days after menopause, but if there is vague pain in the lower abdomen and vaginal bleeding, ultrasound is needed at any time, and specific tests and treatment are recommended according to the doctor’s prescription.