Scan date doesn't make sense!

[SprogletsMum]

I went for an early dating scan today, I thought I'd be around 7 or 8 weeks (Midwife pushed for me to have an early scan as lmp was in April). Scan measurements have dated me at about 5-6 weeks.
I got my positive test 3 weeks ago with an afternoon wee on a clearblue digital which said 2-3 weeks. I know they're not hugely accurate but surely if I was 5 weeks now I couldn't have possibly got a positive test 3 weeks ago?
We saw the heartbeat so not worried as such just a bit confused! Has anyone got any ideas of what could be going on?

This does sound strange. But if you thought you'd be at least 7 weeks and the scan shows at the latest 6 weeks then there isn't that much difference.
I've googled "scan shows 6 weeks should be 8" and there are a lot of threads. So if you don't get an answer here maybe look at those just for reassurance.

Three weeks ago, the test said 2-3 weeks. The scan said 5-6 weeks. So both add up and give the same date.

Although as I was typing that, I realised my mistake, which would have given a positive test pretty much on the day the baby was conceived.

The sensitive Clearblue tests give a result pretty early. I tested positive with DS before my period was due, when I woke up one morning absolutely certain I was pregnant.

So if you were medically 3 weeks pregnant when you did the test (so one week after we conception) then you would be 6 weeks at the scan. And that would work with both tests, probably.

I don't wish to worry you but if you are sure of your date of conception then it's possible the embryo is not growing properly. This happened to me and I had a miscarriage. This is incredibly common.
I wish you luck though

The clearblue test measures weeks by measuring the hcg in your wee. This can differ a lot ( think 25 - 7000 or something in the first two weeks) so maybe your hcg was so high that the test measured wrong? Btw, high hcg is generally a good thing.

Not sure but this could be an explanation.

I was told I was 5 weeks at my early scan (I was a bit confused about dates but thought I should be 6 weeks but I didn't argue) and my 12 week scan I was told I was 13 weeks and they have stuck with the new date ever since. Sometimes when it's very early on they can be a little bit out! I wouldn't worry about it too much, wait till your next scan - you never know they might change your date again!

Hopefully they're just a little bit out because of it being so early then. Had a quick Google and lots of the stories are of people measuring smaller because they had miscarried but none of those stories had a visible heartbeat.
Just had a quick look on the scan sheet and she's written that the view was restricted due to increased bmi, my bmi is 23.7! Feeling like a fatty now too.

A heartbeat is a very positive sign so try not to worry too much. Pretty shitty that she commented on your BMI (and a normal one at that). I am nearer a BMI of 30 and no comments have been made despite being pretty much assaulted during my scans to get through the flab!

I think you just have to take it day by day. I was told at an early scan (where I was worried about miscarriage due to previous history) that at that early stage the baby is so small it's easy to get measurements wrong.
This pregnancy dated behind by a few days at 6 and 8 weeks, by 10 weeks baby had caught up to my dates and by 12 weeks had added a couple of days on.
Equally I've had good scans with heartbeats that have ended in miscarriage. At this stage unfortunately you can't tell either way it will go or do anything to change things. It's more than likely that everything will work out just fine. Good luck

Slightly confusing as it's unusual to see a heartbeat before 6 weeks. If you are 6 weeks (plus a few days) then that fits better?

I had a scan around 8/9 weeks that dated me a week behind my nhs scan at 12 weeks. Baby is now a healthy 1 month old keeping me up at night.

Thanks for your replies everyone, thought I'd come back to update. I had my 12 week scan today, according to the dates they'd given at my last scan I should have been 12 weeks exactly and I'm 13+1. So my thoughts on how pregnant I was were more or less right.