If the menstruation is usually regular, the cycle is once every 28-30 days. If it has been 40 days since menopause, it is often normal to see the gestational sac by ultrasound and in some cases the yolk sac can also be seen within the gestational sac. If the gestational sac is not visible at this time, and there is still no echo of the sac in the uterine cavity, this is clinically abnormal. It is recommended to have a blood test for HCG and progesterone and to have another test every other day to see if the blood HCG has doubled from the original level. If there is no doubling, ectopic pregnancy is highly suspected and hospitalization is recommended for observation.