diagnosis of miscarriage, but no symptoms and have only had one ultrasound, confused it's wrong

My daughter has had 1 ultrasound and was told fetus has not survived and to wait out miscarriage, but there has been no bleeding or cramping and we're worried there might have been a mis diagnosis, she is to see her dr in 4 days if nothing has happened and he will give her something to bring it on, we would like a second ultrasound to be absolutely sure this fetus is not living before we go any further, do we have the right to request that?