Discrepancy in scan dates - worried

[chattycaterpillar]

Three and a half weeks ago, (29/0/2022), I had an early viability scan. It was a vaginal scan, and I was measured 6w0 day with one heartbeat. The CRL was 5.07mm.
A couple of days ago I experienced some light brown spotting. My GP referred me to the Early pregnancy unit for an early scan, but they refused to scan/ see me, ( they said they were currently only providing NHS scans to people with bright red blood, which fortunately I didn't have).

They advised the only thing I could really do was get a private scan, which I did, as I didn't want to wait over three weeks for the 12 week scan worried the brown bleeding was a sign of silent/ missed miscarriage.

Today I went for a private scan, ( different company), and they gave me an abdominal scan, ( they didn't offer a vaginal scan). They said there was a heartbeat, ( which I was very, very relieved to hear !), but when she initially measured the baby it measured at 9 weeks 1 day. She then did it again and the second time the machine showed 9 weeks 2 days, with a CRL of 25.1mm.

Is it very worrying that this is 2/3 days out from the earlier scan ? Or is it affected by the fact the first scan was vaginal and this was abdominal ? Thanks for any advice as I'm now worried the fact the baby appears to be 2/3 days behind could be bad news. I won't be able to afford another private scan, so the next scan will be the NHS 12 week scan.

The reason why early scans are usually advised against is because of the uncertainty and worry they can cause. Remember, the baby is being measured in fractions of a mm and it’s very easy to be slightly out; even the angle of the baby can make it different. The measurement to focus on is the one at the dating scan and also remember that seeing a heartbeat early one really reduces your risk of miscarriage.

There is no safe time in pregnancy but nothing you’ve written suggests anything to cause worry, although I appreciate it’s easy to say that but very different to do. I hope all goes well.

The scans are so inaccurate that they can be wrong by as much as a week. 2 to 3 days is well within the error bars. Please don't worry, your baby sounds like they are growing fine.

I think that’s fairly normal. My dates always shifted a couple of times in the first 12 weeks (complicated pregnancies with lots of scans), everything is so tiny that there is bound to be discrepancy, especially with it being a different type of scan with different equipment. The healthy heartbeat is the main thing to look out for, good luck OP!

Yeah, I guess there is no safe time, I'm hoping seeing a heartbeat at 9 weeks is a good sign. I've also had covid, (today is my first day out of isolation), and although I was asymptomatic, I'm very worried covid could increase the risk of miscarriage/ complications.

@chattycaterpillar

Yeah, I guess there is no safe time, I'm hoping seeing a heartbeat at 9 weeks is a good sign. I've also had covid, (today is my first day out of isolation), and although I was asymptomatic, I'm very worried covid could increase the risk of miscarriage/ complications.

2-3 days "out" sounds pretty normal at this stage,my dates shifted by more than that with early scans. What I've read about covid is that it doesn't increase chance of miscarriage, but can cause problems if you have it later in pregnancy (ie 3rd trimester). Try not to worry so much (impossible task, I know). Everything is going fine right now and that's all you can ask for. Congratulations on your pregnancy

They're so tiny at that stage that it's easy for them to be a few millimetres out. My first scan my DD was at 9 weeks and I measured 8+4, then when I got to the 12 week scan expecting to measure 11+4 I measured at 13 weeks.

Current pregnancy went for a scan at 10+4 and measured 11+1, then a week later at the 12 week scan measured just two days ahead instead of the 4 days ahead the other scan had put me.

t this rate I don't think I'll stop worrying until after the baby is born lol