People have mixed up estimated day of conception with the scan measurements date.I'll explain.When you get pregnant before you have a scan they estimate your due date by your last period.So they count 40 weeks from day 1 of your cycle and as most people ovulate 14 days after day 1 of their cycle the estimated due date has 2 weeks added to it.Scan dates measure the size of your baby since the day of conception good luck

is that really true? i have been thinkin about the same thing i had my first scan on the 19/10/09 and they said i was 8 weeks and 3 days pregnant, the first day of my last period was 17/08/09, i was worried when i read on the internet that they add 2 weeks to an ultrasound, so thought i might be 6 weeks and 3 days instead, but the nurse didnt say she had added 2 weeks on so i presumed i was 8 weeks and 3 days like she said. she said i concieved between 27th of august and 3rd of september, so is that right? do they not add the 2 weeks on after an ultrasound? thank you x

i had the same problem i had sex with a guy on new years when me n my bf wer broke up n had a period 2 weeks later. n didnt have one in feb. they said i got pregnant at the end of jan. i got back with my bf while i had my menstruakl cyce in jan. The ultrasounds were right. i was so scared probaly as much as you are. But at my 32 week ultrasound the babys measurements set my due date back 4 days. But it was still after my period when i got pregnant. so if that helps you They are about a acouple dys off i wouldnt say weeks.

And i just had my babyboy October 12 2009 and he is adorable. And they guy that i slept with on new years was hispanic and my bf is black n my beautiful son came out black.. So the ultrasounds are very much true if u ask me..U should of seen me every visit i had id look at the gest