A gestational sac
should be ideally seen around the 5 th week in a normal pregnancy
. In addition, within the sac, a yolk sac is found around 6th week.
By the end of 7 weeks, the fetal heartbeat should be detected on an ultrasound
Going by your history, you are 8 weeks pregnant as per your last period, and the gestational sac says you are 6 weeks and 1 day pregnant.
Even if we consider, your actual gestational age
as 6 weeks, a yolk sac must be found by now. If we consider that you are 8 weeks pregnant, then the heartbeat should be visible on the ultrasound. Both these findings are not seen in you.
Therefore, I probably agree with your doctor that it is a blighted ovum
. You could probably wait for few more days, repeat ultrasound one last time and go ahead with the procedure of D&C.
Hope this helps you.