I dont understand why my scan was 2 weeks ahead

[mum_since08]

Hi, I had an ultrasound on December 1st 2009. The scan showed I was 10 weeks 1day due 28th June.
The first day of my lmp was 17th September which gave the due date of 24th June. My dr said even though there's only a 4day difference, to go by the ultrasound as its more accurate when scanned early on.

My question is, When i put in my due date 28th June, It says I conceived 5th October. When i count from 5th of October to the 1st of December, It says im 8 weeks and 1 day, not 10 weeks and 1 day. Why is this?

Because I know on December 1st i was 10 weeks and 1 day, what day would I have most likely fallen pregnant? Would it have definitely been in October?

[MarieMac698]

My guess is September 28,29,30 or October 1,2,3 aprox If your cycle is normal 28 days It would be around those days

[angelamary]

Sorry, I had a hard time working that out in my head. But if it helps, My last menstual day was Sept 19 and I am due June 26 and I know I conceived Oct 4th or 5th and that was a 14 day ovulation. It totally depends on when you ovulated that month, but it sounds like Oct 5th is around the right date. I don't know if that helps or not. :)