16wk scan , femur length

[ecossegirl91]

I’ve just been to find out babies sex privately at 16+3.
sonographer was very happy, it’s another lil boy!, and everything was measuring average such as head tummy however the femur she said was a little below average, from the screen it looked to be 23/27 percentile. She then went on to say she had zero concerns and not to worry. However I just wonder if anyone had any advice?

I think they only worry if the femur length is the 3rd percentile or less. One of our twins has a femur length on the 12th percentile and they are not worried, the second twin with femur length <1st percentile has just been diagnosed with T18.

So sorry about one of your twins x

If any measurements are less than 10th centile they would keep an eye, less than 5th is of concern. Your baby's is perfectly normal and what she said 'a little below average' is exactly that. The same way adults come in different shapes and sizes, so do babies. Some bigger than average, some smaller. Baby potentially might be on the shorter side if the measurements are accurate. Having said that, the femur length on one of my scans was on the 23rd centile and I queried it because myself and DH are tall. Sonographer re did it and got 75th centile so just another perspective as the measurements can be wildly off! Wouldn't be worried in the slightest though OP.

Thanks for your reply, that’s helpful.
I also emailed the private scan place and she said not to worry at all, and everything was within normal limits and basically saying what you said - some babies are average, some above and some below. Not everyone can be average.
only 3 wks till my anomaly scan so not long at all!

sorry to jump on this... i am an absolute nightmare googling everything! We have had a rough ride to get here, had vanishing twins at 7 weeks in one sac and have have 7/8 scans so far after this with
everything being great. However,
i am so anxious after reading about femur lengths
my scan today was at 16+1 (although with ivf embryo transfer date would be 15+6)!

Our little girl is in the 19.6'percentile for femur length. All other measurements are average.

ratio of Fl/AC is 18% and should be between 20-24 and FL/BPD is 55% and should be al least 71%

The only thing calming me albeit very slightly is that my son nearly 6 had very short legs at birth thanks to his dad but he's nearly grown into them!
everything has been low risk on NT scan at foetal medicine centre and NHS.

I am probably unhinged but it has taken 4 yrs to get
this far!