Dear Madam, I empathize your situation. The growth of the baby is up to date; however, the heart activity has stooped indicates that it is a recent foetal death. The baby is no more viable. When in such situation the process of miscarriage has not started, it is called as Missed abortion. Urine pregnancy test will be of no use at this stage since it requires a week to 10 days for the pregnancy test to become negative. Now that the diagnosis of foetal death is confirmed by ultrasonography, I would advise you to undergo the termination of pregnancy with the help of your Obstetrician. Delay in termination is associated with complications like clotting disorder (DIC) leading to alarming bleeding, infection, kidney failure, etc. You should not loose the heart. Probably this baby had some abnormalities which had rendered the continuation of pregnancy incompatible. After completion of abortion if you subject the baby for study, you will come to know the fault which might help you in taking due precautions next time. Considering your age, aged egg also could be one of the responsible factor. I hope I have given you due guidance.