i had a scan done very early at what i thought was 6wks3days and an OB did only a external scan (not sure why??) but there was no heartbeat and was measuring at 6wks. It was VERY stressful for me to then wait another week (after having a MC with our first pregnancy) to see my normal OB and then find a heartbeat and to see little man was measuring at the correct dates.

I think everyone is different as to whether they would find it more stressful not having a scan or having one and not seeing a heartbeat that early but i think in hindsight i would have preferred to NOT have the first scan and just have NORMAL anxiety lol if that makes sense!