Date from scan or last period?

[plentyofsoap]

Hi, I had a scan last week that put me at 10+3. She stated in the scan that she would date just in case I decide not to have another scan at 12 weeks. I saw the midwife at booking in on tuesday who stated that she would use the first day if my last period. That is fine, but there is over a weeks difference between the two. I am therefore confused which is currently not difficult to do! What date would you use?

sorry posted it again.

I'd go by scan dates as until a certain point all babies grow at roughly the same rate so it should be fairly reliable. Whereas everyone's cycles can differ and you don't know the exact date of conception (even if you know when you had sex, conception could have been instant or a few days later, you just don't know). Having said that, your estimated due date is just that, estimated. If you go into labour any time from 37-42w it is classed as normal.