Can an ultrasound measurement be wrong?

[gb000]

Ok this is a random qn. But does anyone know if the NHS ultrasound machines automatically transfer measurements to the computer that generates your report; or if they're typed in manually (and therefore at risk of typos)?

Basically today I had a growth scan today and I am 100% sure I saw on the screen that the femur length was 7% (which I think means 7th percentile). But the techs didn't seem worried and when I got my report it shows the femur length closer to around 20% on the little diamond graph (63.8mm).

Now I'm worried that they typed the length in wrongly and based their "not worried" stance on that. Even 1mm - if they typed in 63.8 instead of 62.8 - that could take me from around 7 to closer to 20.

Any thoughts? I'm 35w tomorrow.

They physically click it on the screen. So they manually click point A and B and then the computer measures that distance. They also usually check it several times over and take an average, as the angle baby is at matters so much. So the 7% you saw was just one attempt (if that's even what the number meant!)

Right, but I mean then how does that measurement (or the average) get from the screen I see to the report - is it automatic or do they type it in afterwards & hence could make a typo?

I appreciate this is an absolutely mad specific question 😂. Finding myself highly anxious!!

I've had tonnes of scans and all the screens I've seen the screen at the time of measurement itself doesn't give you the % percentile - it gives the length in mm and then gestational age or another ratio eg head circumference to femur length.

I am a sonographer. It might have been 7th percentile but they took another measurment and got it at the 20th percentile. That’s if they put the Edd into the US machine before they started. I generally don’t. In which case the 7% you were looking at might have been referring to the settings or something. Either way 7th centile is nothing to worry about for femur length even if it was that.