Femur length below 3rd centile 20 week

[Anna2894]

Has anyone been told at 20 week scan that femur length is below 3rd centile? I'm worried sick

One of my scans around then had the head measurement off the scale at the large end and the femur length tiny. Nothing was said so when I saw the measurements on the way home I called and asked the unit if it was a concern (I had convinced myself of all sorts of things) and they said they’re not very accurate!

Thanks for replying! It's my first pregnancy so I don't understand much of the measurements etc. I got pulled to one side by the midwife and was told that I need to come back in for a scan in 4 weeks time and she mentioned a referral to a consultant at another hospital if no change, no idea what they specialise in. Think I got too upset to ask the questions I needed to ask. I've worried myself over Xmas and I don't think Dr Google helps! Cross fingers for a growth spurt 🤞🤞

I know I ignored this advice myself but please do not google. Write down all your questions as in the moment it is easy to forget. Hope that it is nothing to cause further worry

@Anna2894 slightly different situation as I'm only 16 weeks but I had a scan last week, as I have a heart condition and baby's femur was also measuring very short, the consultant is doing my 20 week scan to see if it catches up!

Let me know how you get on with your 20 week scan 😊 I've read so many positives online now (I've been through the bad bits, too) The femur measurements for mine at 20 weeks were 27mm which is 'worrying' as all other measurements were OK. I'm back on the 21st of Jan to see if there's any changes. I'm hoping it's down to me and partner being small

I will do @Anna2894 my 20 week scan isn't till 28th jan, I just looked baby's femur was measuring 16.5mm at 15 + 2 the head and abdominal circumferences where in between 50th to 75th centile, the femur was between 5th and 0 centile, so similar to you!

We're in the best hands now and it's a good thing that they're keeping an eye on it. I'll update you with the 24 week measurements😊

My girl twin at 16 weeks onwards (now 32 weeks) has consistently had a femur length below the 2.5 centile. I get monthly growth scans and the doctors are happy as long as she grows consistently which she is. She's just going to be much smaller than her twin brother. Also Im only 5ft3 and my DH 6ft4 so clearly she is going to take after me and her brother take after DH!

If it helps and you have the other measurements there are a few ratios eg head circumference to femur length ratio which is more of an indicator If there is a risk of something being wrong

My baby's femur was measuring short (under 9th or something) his abdomen was over the 97th and all other measurements were on the 50th. We had regular growth scans but he was born last week absolutely perfect. He just might not be 6 foot tall as an adult.

I had SO many growth scans with my youngest because she measured so small - she was 7lb 10oz when she was born and is now tallest in her class. Try not to worry and read too much into things, I know it's tough especially with your first.

Both my twins measured off the scale for short legs! Both born with very normal length legs. It's all a big worry but chances are everything is fine. Babies are so tucked up inside that the measurements can easily be inaccurate. Neither of mine even made the centiles and it put the fear of god into me and ruined the pregnancy but they arrived perfect

Hi

I recieved similar sort of information for my daughter on her 20th scan, we had another scan about 6 weeks later and her measurements had caught up.
I was also told my daughter would be short and I shouldn't be surprised as I'm only 5ft.
She is almost 6 now, with lovely long legs and is tall for her age..! X

Oh, I haven't found these ratios.. Yet 😂 I've found all sorts of graphs and estimated weight calculators etc..
My baby's measurements were
AC 146mm 46 centile
HC 170 39 centile
FL 27 1st centile

Has anyone had any experience with them measuring the tibia and humerus due to FL being so small? Mine were measuring at 16 weeks + 6 days. I believe this is why they're worried?

Congratulations 🥰♥️

When I was researching my little twin measurements I read that it's when the femur length is 3 weeks or more behind gestational age is when they start to worry? But with my little twin they moved her gestational age on by 5 days because her brother was measuring bigger which also distorted things.

The ratios can be a bit scary - the FL:AC ratio for dysplasia or downs I read should be between 0.2 and 0.247 - the first few growth scans I had my little twin was smaller than this like your baby's is but around 28 weeks it has started to creep over 0.2.

I'd already had the NIPT done at 12 weeks so before they became concerned about her size - the NIPT came back low risk - they said i would have been offered CVS/Amnio had I not had that done

Hello, I just wanted to check the outcome of this. I am 25 weeks pregnant and the Femur is measuring at 3% whereas everything else is measuring normal. I never did the downs syndrome test as I misunderstood the midwife at the time. I had an app today and the doctor was pretty sure that the baby is fine and it's just a small baby but wanted to know how you got on in the end or if anyone else can help. I am now really worried!

If it’s below 3rd centile then I assume it’s the 1st or 2nd one. By definition 2% of babies will be at this level - so 1 in 50 parents will have been told the same as you. Sounds like your child might be on the short side if they’re amongst the 2% of shortest people but I wouldn’t say it was anything to worry about?

@SarahOK5101 I went through similar myself earlier this year, femur measured below 3rd percentile from 20 weeks. I had multiple growth scans and it was always below the 3rd.
I also didn’t get the screening as my baby wouldn’t stay in the correct position.
The outcome for me was a small baby, 4lbs8 but perfectly healthy, she’s just gone 6 months and she’s still petite but no growth issues.
I spent nights googling what it could mean and peoples experiences so totally understand it’s worrying.

Thank you for getting back, this is reassuring. My daughter who is 16 months is petit but she was never small on scans and she weighed about 6 pounds. I'm about 5ft and my husband is 5ft9 so we aren't exactly a tall family! It's very scary and worrying when the doctors are saying other possibilities it could be that gets you really worried.

@SarahOK5101 I went through the exact same with doctors having to mention other possibilities and to be honest it totally ruined my pregnancy from 20 weeks as I was worried about it. Myself and my husband are also not tall and I was told the same by the fetal medicine unit that she’s likely just small as we are…not that it stopped me worrying!

Her other measurements were around 30-40th percentile and she always grew scan to scan it was just always the femur that was really small.

I did have my baby at 37 weeks I should have said so she was a bit smaller due to being a little early also.