Femur length

[needhope]

Hi

I had some issues with an early Nuchal Translucency scan – the babies NT at 12 weeks 6 days was 3.7mm. It was re-measured at 13 weeks 5 days and was only 2.00mm (completely normal). It has always been a bit confusing as the 3.7 measurement was taken on a tilted uterus and the sonographer had a very hard time getting the pictures whereas the 2.0mm was done by a specialist who got very clear pictures because by then my uterus had popped forward.

I had blood tests too which were completely normal and ended up with a Downs Syndrome risk of 1 in 154 (my hospital class anything over 150 as low risk so we were just low risk in theory), we therefore declined CVS or amnio as I have already had 2 miscarriages. However we did agree to have a heart scan and anomaly scan at 19 weeks by the specialist again.

I had these scans yesterday and the reports they gave us said that as far as they could tell, the fetal heart and anatomy was normal and they didn’t give us any further cause for concern. However when I got home I noticed on the growth charts that the babies femur is measuring slightly shorter (around the 15th percentile)> A couple of the other measurements were under 50th percentile also and none of them were that far over so none of the babies measurements were that big I suppose but the femur one was a bit lower down the scale than the others.

Anyway I had previously read that short femur can be a soft marker for downs syndrome? Should I be worried about this or am I being completely ridiculous?! The consultant didn’t even mention it to us, just said everything seemed normal, its only because I read the report in detail and saw all the measurements? Does it probably just mean that little boys legs need a bit of a growth spurt? My husband was cross when I even mentioned it to him as he said that if the consultant had thought it was an issue he would have said so!

Has anyone else had anything like this?

xxxxxxxxxxx

 

[beetroot]

The doctor would have said something if he was worried especially as he has followed you up from your original NT scan. However, if you're worried, I would give the doctor's office or ultrasound department a ring and ask for a chat about it just to put your mind at rest. After my anomaly scan I was worried about one of the measurements being on the 5th centile so I rang up the ultrasound department and someone rang me back and put my mind at rest. If you know you're going to worry about it, try and speak to someone.
Babies come in all shapes and sizes, and at this stage grow at different rates, so try not too worry. xx

 

[michellle1980]

I think we are programmed to worry. There was a thread the other day people worrying about measurements being too long. I would call your midwife/ doctor as only they can really answer your questions.

I seem to worry about everything. I keep thinking when I get to this stage i can relax but realistically I think I will still be at it when they are 18 years old.

Hope you find out to put your mind at ease.

 

[Jaysmummy]

Do you know what the exact measurement was hun?

My last baby also had a reading of 3.8mm and then a week later it had gone down to 2.8mm. I was given a 1:89 risk and then combined with bloods it went to 1:270 so I declined CVS and Amnio.

I had to have regular growth scans and at every scan his femur length was always below the 50th centile on the graph but not below the bottom line. I think at 20weeks it was around 30mm. I also did the same as you and thought the worst especially as his head and abdominal circumference were always above average.

He is now 18months old and perfectly fine and healthy! He was also pretty big at 9lbs 10ozs So just goes to show don't presume the worst and there are plenty of soft markers that sonographers look for.

This baby's femur is also measuring just below "average" at 31mm

xx

 

[nlz2468]

What size is your babys femur legnth measuring hun? Mine was 30.9mm at 20+4weeks then it was 41mm at 24weeks. Mine is on the lower end so shorter legs! My NT scan at 13+4weeks was 3.6mm and i was told i had a 1:1350 chance of having a downs baby!

x

 

[needhope]

Thank you for your replies that does make me feel a bit better.

The babies measurement was 28mm at 19+4 so doesnt sound that too small actually? The graph they gave me plots the measurements on the 5th to 95th percentile and it was on about 15th i think? So like you, not below the bottom line.

The consultant didnt even mention it to us (although obviously he knew we were there due to the downs syndrome risk) - it was only because i noticed later on and am a natural born worrier and had read something about that and downs syndrome! They didnt recommend any further scans and i guess they might have suggested more if they were worried? Other than the inital NT measurement they didnt see any other markers at my early scans and said everything was normal at this scan.

I need to relax dont i?? My husband just said 'Well all babies come in different shapes and sizes so dont worry!'

Hard though isnt it! Why cant i just let myself enjoy this! i think there seem to be different interpretations of the NT scan too - they scared the crap out of us with the original 3.7 measurement and within 5 days it was completely normal. Both my hcg and papp-a came out at pretty much 1 MoM so totally average.

xxxx

 

[Akinesia]

After noticing on my scan that the U/S tech had measured my baby's head as being larger than average, yet most of the other body parts as being either normal or smaller than average, I asked her if that means something is wrong. She pointed out something that made me feel a lot better, that these are all simply averages and it's rare you'll actually find a baby that perfectly fits into all of the average measurement categories. Chances are some parts will be larger, and some smaller because every baby grows differently. Then they take an average of all of these measurements and calculate roughly how far along your baby is measuring. My baby's measurements balanced out and matched my due date.

I also thought more about this when I got home, and I have a larger than average head circumference... so does OH. So no wonder, our little one takes after us. It might just be that your baby has inherited slightly shorter than average legs from somewhere in your or your OH's genes.