12 wk dating scans - completely wrong apparently!??

[Millie26]

I had scan in wks 5, 6, 7 and 9 and every time they said the crown to rump measurement or other factors meant it was exactly 6+1 or 7+4 and it all added up every time to the day so I thought I knew exactly.

My 12 wk scan was yesterday and I should have been 12+1 but the sonographer said I was 13 wks exactly.

When I told her about the earlier scans she scrubbed out my due date and made it a week later and said the early ones were more accurate.

I think a week out at the 12 week stage is pretty off the mark. Why dont they do everyone earlier?

Or am I being stupid? Had to rearrange my nuchal scan just in case I was over 13 + 6 as they weren't happy about it.

I thought the dating scan was supposed to be really accurate?

tbh, I have never trusted them, I can't see how on earth they can be completely accurate. In the end, if you knw your dates, then you know, and if the hospital dates don't tally up, I always go with my own. Wouldn't worry too much though. Both times I've been told that dc was smaller/younger than I thought, but guess what, the arrived on my due date!! ime it's better to have nuchal scan later than earlier if in any doubt

i just got 8 days taken off my dd, i am 29 wks.

last pg my doctor estimated an extra 7 days when i was around 37 wks.

its not a completely accurate thing, its based on averages

mine were all over shop at 6/7/9 then consistent with what i thought were my due dates from 12 weeks on . It is completely average thing and given how little it takes to vary the dates before 12 weeks it not surprising it moves. doc still ended up putting a few days on so didnt get induced.. nd he was right to in the end

They usually do them at about 12wks because (unfortunately and very sadly) many pregnancies don't get beyond this point and to do a scan before would:
a. cost money
b. probably cause the mother more heartache after she had seen her baby on the screen
(Thats what I'm led to belive anyway)
The dating scan is accurate up to 12 weeks or there about, but after this babies tend to grow at different rates.

My first dating scan showed that I was only 10+5 weeks - but I knew I was 12wks - I KNEW because I knew the exact date I concieved because it was the only day we didn't use a condom He was born 2 days late (to the dating scan date), but the midwife said he was definately later because of his skin. So I don't think they can be 100% on it anyway.

On DS2, the dating scan was one day before My dates - so they had it pretty much spot on - and he was a week late! (again his skin was really peeling because of "over cooking")

I wouldn't worry about it if I were you - he/she prob won't come on the date they give you anyway!

They don't do nuchal scan here - you just have to have the blood tests done instead (which I always refused)

I had my dates moved back by 3 weeks last time even though DH and I were fairly sure of our dates.

I developed PE and was induced 3 weeks early but had been in labour for several hours the day before, confirmed by a midwife. It stopped just before I was due at the hospital, probably as I have a stupid, irrational fear of hospitals.

DS was 8.4lb and everyone commented on how he looked like a full-term or every overdue baby. He didn't have any wrinkles at all. He was born 2 days after our original dates.

Babies come out when they are ready regardless of the guessdate that they put in your paperwork so I wouldn't worry too much unless it means that you are at risk of an induction.

I've had fertility treatment and know my dates down to the hour (), and both my babies have been big-for-dates at 12 weeks. The midwife said that they would use the scan date, as that was "policy" which I suppose I can understand (as so many pregnancies are accidental, and in that case you would probably be a bit uncertain of dates). It's really annoying though.
I bet that it's cost that stops them from doing an earlier ultrasound scan. The nuchal fold was part of the 12 week scan at my hospital (not sure if this is for everyone, or just old farts like me) and it would double the costs to do both.

if you disagree with their dates, you can always cross them out in your notes and write your own in. midwives generally assume another midwife did it