Early pregnancy scan worry

[Ponyolikesham]

Hey, I’m hoping for some advice or reassurance...

I had an early ‘reassurance’ pregnancy ultrasound scan today. I’m supposed to be 8 weeks + 3 days, but I’m apparently measuring 6 weeks + 1 and measuring 4.6mm.

They didn’t seem worried even though I told them I am adamant that my dates are correct. We could see a heartbeat which was slightly reassuring.

The problem is that I had an early scan with my first baby at pretty much exactly the same time and it was measuring 19.1m and looked much more like a baby in the photos. How can the measurements for this pregnancy be a quarter of the previous one?

I know there must be some margin of error and maybe since my first pregnancy I now ovulate at a different time in my cycle? The days between last period and my early scan was 57 in my first pregnancy, and 59 this time, so if anything I would expect to me measuring slightly bigger.

Bracing myself for bad news now, but just wondering if anyone had similar situations and what ended up happening?

Thanks in advance

I haven't got much advice but the measurements on those scans can me marginal. They use a measurement on the screen to measure it and a slight difference in where they sit the line can make many days difference.
I got put back 9 days on my early scan and then at my 12 week scan, I was put forward 6 days

Thank you for responding. I’m hoping that the measurements are out, but it’s a difference of 16 days which seems high.

They have advised to go back for another scan in 2 weeks time to see what the progress it, but to be honest, I’m scared to go.

Unfortunately for me I never had a good outcome - measuring up to a week behind is generally ok but 2 weeks or more if you are certain on your ovulation timings etc it could go either way - really hope you get good news in 2 weeks x