Some Obstetricians ask to do a scan at 8 weeks, as rayray said, you may not find a heartbeat until then. Basically it's a dating scan, plus, they want to see if the pregancy is viable. SOME obstetricians believe that if a heartbeat is found at 8 weeks then it's unlikey a miscarriage will occur. My Obstetrician sees people at 10weeks as he thinks this is a better indication. I would say there is no problem with leaving it till 10weeks, if you are sure of your dates, or within 2 weeks at least, as the 12 week NT scan NEEDS to be within certain dates (12-13weeks I think), therefore the early scan is also to be sure the NT scan is done at the correct time.

Gees, I hope i've made sense>>>>>