How accurate are early ultrasound scan results ?

[Micasmum]

Hi guys , anyone experience this please ?

I am currently 8 weeks pregnant with twins through IVF.

So I had a reassurance scan on Tuesday at 7 weeks 6 days as I lost some symptoms and I was measured 8 weeks 2 days for twin 1 and 8 weeks 1 day for twin 2 with perfect heartbeat.

This showed that babies were measuring ahead by 2 days.

I was having my first prenatal appointment the next week and assumed they will ask me how far I am as it’s an ivf babies.

So to be sure of the measurement, i went for another scan 4 days later ( Saturday) and the measurements matched my initial measurements; 8 weeks 3 days for twin 1 and 8 weeks 2 days for twin with good heartbeat .

Now they are measured 3 days behind from the last scan on Tuesday but matches my calculations.

I’m confused if something is wrong or the sonographer on Tuesday got it wrong or this is normal.

Anyone had similar experience please?

Thanks

[raverg]

First of all, congratulations!

Secondly, there’s a margin of variability allowed in the measurements (+/- 2 days I think but could be more) but also a margin of error with the sonographer’s measurements, since what they’re measuring is the size of mm’s at this point and where they put their dots matters so much.

Were the two scans done in the same place? You could wait for another week and try getting a third, but so far things sound good and the heartbeat is very promising.

I found that despite knowing exactly when the day 5 embryo went in, my IVF consultant and my maternity could not agree on my exact due date, even though they were starting with the same transfer date 🤦🏻‍♀️ there was a 2 day difference between the two dates but in the end I went with the maternity’s as it matched my calculations too, and as time went on, measurements followed that date along +/- 2 days without the sonographers looking worried.

Hope this helps! And all fingers crossed!

[Micasmum in reply to raverg]

Thank you so much. It was a bit worrying couple with the fact that I lost my symptoms. But thankfully everything is okay. I had some spotting that took me to EPU and I was scanned and babies were growing at 9 weeks plus already (meaning the first sonographer was right) . Maternity booked me for a 11 weeks scan rather than 12 weeks, which I don’t mind, she said she’s following my last period not my transfer date . So we’ll see what happens.

[raverg in reply to Micasmum]

So pleased to hear from you and so pleased that the babies are thriving in there. Hopefully you won’t need any more EPU visits 🤞🏻 interesting about the 12 week scan happening at 11 weeks!

[Twiglet2]

babies don’t grow exactly as they should on the chart, they can measure ahead and then behind etc. by a few days. As long as they are around where you think they should be then it’s absolutely fine, especially with twins (congratulations!) stick with your IVF dates just now for due date and at your 12 week nhs booking appointment they will set an official due date then based on your sizes at that point (or they may use your IVF date depending on your health boards approach) but defo all sounding absolutely normal at this stage and nothing to worry about xx

[Micasmum in reply to Twiglet2]

Thank you so much. Babies are growing well. Checked on them on Tuesday. It was funny because in one scan, one of the twins had different measurements(+\-1 day ) . Then I understood that the position matters.