Can dating scans be wrong?

[Bubble04]

I know this sounds daft, but is it possible for dating scans to be a month out? Has it ever happened to anyone?
I'm 31 weeks and have had 2 previous DC. Hard to explain, but I just feel further on than I am. Getting loads of 'last few weeks' symptoms, and she is strong. Really strong. Also, measurements are consistently significantly ahead. Last one estimated baby is already 7lb (awaiting growth scan). At the beginning of the pregnancy I got my bfp at 7dpo and it was dark, and my last period was very light.
I know I'm probably clutching at straws because I'm so uncomfortable now, but thought I'd see if it had ever happened to anyone. Seems crazy I've still got 9 weeks potentially...

I think it's quite unlikely as a dating scan is done at that time as it's the most accurate time to measure and date pregnancy. They can most certainly be out by a few days or a week but I would think a month is unlikely.

In which case I sincerely hope the growth scan shows they're wrong with their size estimate 😂

What’s the difference between your EDD by LMP and by the scan?

I know that midwives often prefer to stick with EDD by LMP when a woman is sure of her dates but I think it’s really unlikely that a dating scan could be four weeks out. There’s a world of difference between a foetus at 8, 12, and 16 weeks.

I think it's much more likely your growth scan is out than your dating scan. They are notoriously bad at predicting birth weight.

My sisters scan at 12 weeks was 2wks 2 days out (ahead) which was pretty extreme. She had ivf so the dates are certain. She is sticking with the ivf dates.

Growth scans are much less accurate so definitely could be the case!