How accurate are trans-vaginal u/s at 9wks & 6days? do they go back to your lmp or conception date? my edd is 1/22/13, from my 1st vaginal u/s...

More info now: If u are due 1/22/13 then your last period started around april 16 if your periods are every 28 days if not, then u cannot use that to figure out when your period started, and advice from someone who has done over 5000 deliveries, do not go past 40 weeks, new study shows - ideal time to deliver is 39-40 wks- less chance for baby complications, none of my pts go past 40wks and they don't want to.