How accurate are scans prior to 12 weeks?

Question

my wife had an internal scan yesterday - we assumed she was 6 weeks and 3 days from conception (approx) - but the doc instantly said 7 weeks and 5 days...showed us the heartbeat and let us listen to it (wonderful to hear!!)...don't get me wrong - we're not bothered that our own dates were wrong but just wanted to ask the question - are these scans very accurate?

Answer 1

The earlier the scan the more accurate it is. The later the pregnancy, the more room there is for fluctuations between average baby sizes. They use measurements of baby (spine, legs, head circ.) to determine gestation so if they say you are nearly 8wks then I would be inclined to believe at this stage. however if they tell you at 32wks you are 34wks I would be less inclined as you could just be having a bigger baby than average.

Answer 2

the scans are very accurate . The dates are usally correct with the scans but sometime if your baby is big it can be off a little so the doctor will still use the origanal date or the date of the last menstral period

Answer 3

scans beofre 12 weeks are very accurate,
They are able to measure the sack better and that gives them better date, they are most likely 95% right

I thought i was nine week when i have my scan done and the told me that i was only 7 and they are right. my mid wife told me the u/s dates felt more accurate when she checked my belly

Answer 4

ok..Your test on October twenty eighth could have had your due date around the twenty 2d of June. So your later test has in basic terms replaced via 3 days....Scans later in being pregnant are no longer precise in determining LMP, in basic terms due dates...Scans early in being pregnant are greater precise at determining concept (and then upload 2 weeks)....And scans are often precise +/- 5 days...So regardless of whilst your LMP exchange into, you conceived around Sept 25- October 4....desire this facilitates! suitable of success