Femur length 4th percentile, measuring 2 weeks behind

[User1838482]

Anyone have any experience of this? Been referred to fetal medicine but I'm a mess in the mean time.

Yes my dds femur measured on the 3rd.
We got referred to fetal and they told us 'shes being born into the family that made her' (DH and I aren't tall) they then discharged us from fetal.
We had growth scans then every few weeks to check they were still growing.
DD was born happy and healthy just with slightly smaller legs which atm no one really notices until I point it out although she is only 11 weeks

My DS was 2nd centile at birth, still not sure why but he’s absolutely fine. It helped me to remember that the point of centiles is that babies will be right along the spectrum, it’s just that yours is in the smallest 4% (though scans aren’t particularly accurate either). I hope all goes well at your appointment

My DD was just under 5th centile for head, leg and abdominal size.

They put it down to poor placental function and I had weekly growth scans.

She is absolutely fine (perfect). Try not to worry - 4th is still within range and they are very cautious. You will get lots of scans/care.

I think it's worrying me that everything else was around the 50th centile and it's just the femur that's really low on the 4th centile. Seems to be suggestive of dwarfism and other things! Thanks for the responses.

I'm experiencing this too. Growth scan at 34 weeks (currently 36 weeks) showed everything around middle of centile except femur which had dropped off the bottom!! Sonographer mentioned it to doctor, neither seemed too concerned and said my boy would probably just be small. They didn't refer me on or suggest more scans. I googled short femurs and have been beside myself since... I've read everything google has to offer and am in a bit of a panic. Not much I can do now until my baby arrives. When are you due OP?

@User1838482 hey OP how are you getting on with this - any update?

Our DS had very small femur in scans - 5th percentile, we were so worried and frantically googling etc - reading about dwarfism etc

Turns out he did have small thighs but nothing out of the ordinary! Hes now 4 months and 50th percentile for weight and 75th for height.

He just gets his height from his torso and his lower leg. In hindsight we should of not worried so much as me and DP have both got shorter legs and longer torsos so it made sense he would be the same!

@User1838482, how are things? I am expecting twins and had my anomaly scan 2 weeks ago; twin 1 is growing fine and pretty much measures to date; twin 2 was measuring quite a bit smaller with a disparity of almost 22% between them along with having femur length on the 6th centile and abdominal circumference under the 5th centile. Had a repeat scan yesterday as they had not been able to see all the cardiac structures for both twins due to their position (they saw everything they needed to see so that’s no longer a concern) and the sonographer was asked to repeat the femur and abdominal measurements. She also checked the biparietal and occipitofrontal measurements again and recalculated the head circumference. The femur length has now gone up and is on the 8th centile; the abdominal circumference is still under the 5th centile and the head circumference has gone down from the 70th centile to the 8th with the measurement actually less than it was 12 days previously. Twin 2 is calculated as weighing the same as twin 1 did 12 days ago so has grown but now all measurements are showing lower on the centile charts than they did before.

I have been referred urgently to fetal medicine and will be seeing them tomorrow (am thankful I don’t have to wait for the appointment) and am a bit anxious about what they may find from their investigations. I wonder how you got on at your fetal medicine appointment and since then?

Remember - good luck with fetal medicine. I've been referred there too - single pregnancy (22wks) and baby is tiny, placental insufficiency for me. Fyi it can be quite common for twins to be different weights - theres a set in my family and one was well over 1lb bigger. Smaller one was 4lb 8 at birth and is a happy healthy & v intelligent adult now :)

To put things into perspective (perhaps?) my dh is 6ft tall with same size legs as me and I’m only 4ft11! You wouldn’t be able to tell from looking at him but his height comes from his torso as someone else said! And we both have short legs!
I am literally having the opposite with my baby! At 20week and growth scan she is measuring small everywhere but her legs are on 50th percentile 🤣 shocked the sonographer both times because she saw me and was expecting a smaller baby with short legs lol! It does worry me slightly though because it makes the estimated percentile jump up to 14th line despite everything else measuring very small! I have lots of scans booked though so am being kept an eye on and if I have any concerns I will talk them through with the sonographer/mw/consultant!
I would recommend not googling too much though! I get myself in a state over things unnecessarily by doing that!

Thank you @NoIDontWatchLoveIsland, I think what is concerning me is the difference between the twins and that we are certain of dates because they’re IVF conceived. Only a few more hours wait till the appointment and hopefully they’ll put my mind at rest!!

My son had femurs measuring weeks and weeks behind. It turned out fine. He just had short legs

Following on from hospital appointment yesterday and, while twin 2 is still very small, there is growth and measurements today have plotted slightly better on the 11th centile. The Dr did Doppler studies looking at both twins placental effectiveness and she was happy with that but did also say twin 2’s placenta is smaller than twin 1’s. She said, at the moment they don’t need to do any more invasive investigations but she will happily see me again if the antenatal clinic feel there are concerns. So just a little monkey and a slightly smaller monkey!! Their weights today are 542g (1lb exactly) and 386g (14oz) so still a couple of oz difference but smaller twin (2) now measuring between 10-15 centiles and twin 1 measuring on the 50th centile!!

That's great news. I had another growth scan yesterday and my baby's femur length has shrunk. Goes to show how accurate it all is. 😊

@PBobs, you do have to wonder if it’s down to individual sonographers or machines when it comes to measurements don’t you. With my T2 the head measurements had gone down in 12 days between anomaly scans but then risen again (though not by as much as it had dropped by) in the 2 days before the fetal medicine consultant measured it. I can understand the diameter and length changing because of the fontanelles meaning the shape changes based on how they share lying but you’d still expect the circumference to be about the same!!

Hopefully the next scan you have is more reassuring. Mine is only 11 days away as I’m having routing growth scans from 24 weeks due to carrying twins and can’t help worrying a little bit that growth will be off again!!