27 Week Growth Scan - Femur Percentile Drop

[ThePoliteLeader]

Hi

Just had a 27 Week Growth scan. Femur down from 83rd percentile to 10th percentile.

Head size has held at around 30th percentile . abdominal dropped by 10% to 50% but estimated weight dropped from 60 to 14th.

Googling (which i know is a bad idea) has all sorts of conditions such as dwarfism so i am abit concerned.

Anyone else had a similar situation that could let me know how it turned out for them or is going through the same thing?

Thanks

What did the sonographer say?

Didnt comment on it really. just stood out to us.

You’re joking? You haven’t been referred? No concern expressed?

Nope, still within the normal range. everything looked ok apparently

So absolutely no concern
And just waved off happily?
well they’ve seen it - so trust them.

Nope. I think the cut off is under 10th but as they are 10th they just waved it off. Ill try to! its just the drop that got us but the first measurement (or this one) could be off i suppose

The low femur reading could be disproportionately influencing the weight estimate, Given they’re not concerned I’m inclined to think the baby was in an awkward position for the scans and maybe they over estimated the last time and underestimated this time. Whalen is your next scan due?

My daughters femur measurement was always v long and they expected her to be a whopper. She had a funny way of laying (we couldn’t find out sex until 35 weeks). She was very average at birth 🤷🏼‍♀️

Hi, we did have this! It was over Christmas time and I remember just spending the whole time panicking and researching specific types of dwarfism.

Femur was really low ie 3rd percentile, with the rest of the measurements being around 40-50th percentile. We were referred to fetal medicine who did some extra investigations- I believe they were looking at Down’s syndrome although I had had a private NIPT which ruled that out.

After the fetal medicine appointment I was discharged as the consultant thought it was one of those things, although still got brought in for weekly scans. To cut a long story short I did have some kind of blood flow insufficiency which potentially slightly slowed his growth. But it never came to much as he kept growing just enough.

He is at school now and is a little smaller than average - I think a lot of this is genetic though, as he shares many other features with the men on my side of the family who tend to be small.

Thanks for the reply! glad it worked out ok. Do you remember if your babies femur dropped off rapidly or was it always small?

Thanks for the reply :). Baby was in a very awkward position for the 20th week (making it hard to determine gender) and was abit awkward this time aswell so it could be the positioning. No further scans at the moment :)

I seem to remember that the low measurement was at a 28 week growth scan. At the 20 week scan it was all in proportion on the 40-50th percentile so yes, it was a drop off during those weeks..

Strange how things work! ill keep my fingers crossed!

When do you next see your midwife? Id discuss with with them x

2 weeks I think 😄, will do

My dgs's femurs pretty were really short (3rd centile ) coupled with a massive head and large tummy... All worrying.
Turned out he was short with a big head... No dwarfism just him!
He's 5 now, he's grown into his head, but he IS very short.. 2nd centile for height... But a perfectly typical 5 yr old boy! Each scan came up with different measurements and often it's the angle /how the baby is lying, so if the sonographer isn't worried it's probably nothing to be concerned about.

I think they have a margin for error which is the grey area ye are currently in. Scans in my experience are not super accurate, I can see why people pay for extra scans even though I never did. I don’t think too many scans are good for babies either.

Hi OP, at my 20 week scan my baby's femurs were measuring below the 3rd percentile, which is the 'line' for concern (and why they won't have said anything to you). I had a medical scan about a week later where the measurement was the same, and all other measurements were between 30-50%. At that point they said it could indicate a chromosomal issue, early growth restriction or just a short baby (I'm not tall). I was offered amniocentesis which for various reasons I chose, and everything came back clear. I had a growth scan this week at almost 27 weeks and the femurs were up to 14th percentile. I'll have another scan at 32 weeks.

I have spoken to a few people who had the same issue and everything turned out fine for them. Apparently femur measurement is the one that's most likely to be inaccurate, or to cause an issue then catch up. It is also unlikely to cause an issue if nothing else stands out - i.e. certain conditions would also show enlarged parts of the brain or heart.

Sorry for the essay, just wanted to try to reassure you as I understand the worry! x

Scans, however many do not cause any harm to babies. However you are totally right about the margin for error in measurements, they can cause so much unnecessary stress.

Hi, I had a private scan at 30 weeks which showed babies head was above 99th percentile, abdomen was 96th centile and femur was 2nd centile. All these measurements were “normal” at my 20 week scan so this came as a shock. We had all sorts of testing done with fetal medicine, as well as regular scans for the rest of my pregnancy and he continued to follow this new growth chart. All our testing came back “normal” and he was born last week and he is perfect 🥰 doesn’t look out of proportion at all! My brain went to dwarfism straight away when we were told, but that isn’t something the doctors ever mentioned to us. Easier said than done but try not to worry if the sonographer wasn’t concerned!