Most accurate, early scan or dating scan (12weeks)

[Gsb1234]

When early scan and dating scan don't quite tie in what would you trust to be more accurate?

[Gsb1234]

I'm the opposite I feel my early ultrasound was out by 6 days and my dating scan bang on! It's bizzare!  
LG I am also due 6th May x

[AnnieBrooke]

I agree with what Lg is saying -- most doctors, by week 12, will say +/- 7 days when using an ultrasound to try to determine an estimated due date.  But at 7 weeks, they will say perhaps +/- 1 day.  By the time a woman is full term, it's +/- 3 weeks!  :)

[Lg1195]

Im confused, why do they need to to tie together? Because i was told on this that they dont have to as babies just start to grow at different rates after a while, so reading stuff like that just makes me anxious, my first scan at 7 weeks 6 days gave me a may 6th due date and my 12 week 6 day scan gave me a april 30th due date cus i was measuring 6 days bigger...