How accurate were your early scan measurements?

[Elsie2021]

If you had an early scan, how accurate was the dating they gave you when it came to your dating scan? 🙂

I had an early scan when I though I was 8+3 but was dated at 9 weeks. Just interested if I’m likely to get pushed back at my dating scan or if it is still fairly accurate?

Thank you ☺️

My scan wasn't too early, but I was dated 10+3 when I thought I was 10+1, then I was dated 13w when according to the last one I would have been 12w+5 so brought forward by 2 days twice.

I think there is lots of room for change and also quite a large margin of error because the measurements are so tiny. I think I was told the margin of error at 12 weeks was 3 days either way so most changes fall within that anyway.

Best of luck for your next scan :)

Mine moved back and forwards by a couple of days each scan.

First early scan I thought I was 7 weeks but dated 6+5. Had another scan at what I thought was 9+5 but dated 10+2.

12 week scan is on Friday and I'm 12 weeks today going by the early scan dates but we shall see 👀

My dating scan had me 3 days ahead of when I know we conceived.

I think it’s pretty different for everyone tbh!

I’d worked out estimated due date based on LMP. Every scan after gave me the exact same date which I think is pretty unusual 🙈🤣 DS was also actually born on that day 🤣

We knew exactly when each DC was conceived as each time it was an infrequent enough activity for it not to be possible to be another date we'd DTD. DD1's date was out by a little over a week (they thought she was conceived earlier than we know she was), and DD2 it was just a few days in the same direction.

I was wondering this because I know exactly when I ovulated and my early scan put me 3 days ahead but I found this study that suggests the time until implantation might affect dates (with the obvious caveat that at this stage everything is quite small and there is some leeway)

obgyn.onlinelibrary.wiley.com/doi/10.1002/uog.12277