Accuracy of dates- when am I due?

Similar to 'mummyofterror' I am a bit confused about my dates.

According to my cycle- my last period was 8th April, making me currently 9 weeks, 5 days (due 13th Jan). My doctor sent me for an early scan to check on things (long story!) and my dates are different. According to my ultrasound I am only 8 weeks, 4 days (due 21st Jan).

What date am I to go off? How far along am I?
I know that its possible to have ovulated later in my cycle, but I was keen for the 9 weeks, 5 days as its closer to telling people! LOL!

Is it possible that I am 9 weeks, 5 days with a short baby? Do genetics kick in early because my husband and I are both shorties! LOL! Or am I really 8 weeks, 4 days?

Arrgghhh....confusing! None the less: THERES A BABY IN THERE with a STRONG heartbeat (173bpm) and that makes me VERY happy!

I'm of the belief that the early the scan the most accurate the dates. Having a scan at around 8 weeks I would think would be quite accurate. I'm the opposite to you in that I am measuring a week ahead for my dates, but I think that is correct as I think I ovulated earlier, otherwise it is a miracle conception as the was no DTD near to ovulation at around day 14. If there is a chance you may have ovulated later then I think that the scan maybe correct.

Will be intersting to see what your 12 week scan says.

Glad to hear you had a strong heartbeat

My understanding is that genetics dont tend to kick in until after 12 weeks in-utero. That said babies still undergo differing growth spurts at different times so a scan is only a guide. Is your cycle regular? Like a 28 day cycle? Cause thats going to throw things around too. If you go by the 'old' calculations from the 'Every Woman' book your EDD is 18th January, so that throws a whole other ball into play :lol: Dont worry to much about it hun, its only an estimate and bubba will come when he/ she is ready. The main problem with EDD is being pressured into induction when you arent really overdue as such.

I would go off the dating scan too

I would wait until your 12 wk scan before trying to work out what your correct dates are :) Sometimes the sonographers can measure wrong at this stage, if they are out by a mm, it can change your dates by days. Genetics dont come into play until the 19 wk scan, up till the 12 wk scan they do crown to rump measurements. With #6 the sonographer put me 10 days behind my LMP dates at my 7 wk scan. At my 12 wk scan, i measured 10 days ahead and back at my LMP dates. The sonographer doing my 12 wk scan asked if i had had my 7 wk scan there, which i hadnt and she said "Good, cos that would have been really embarassing for us", so the other sonographer hadnt measured accurately.