Short femur length- 36 week growth scan- accuracy of measurements?

[Bobbysmumsy]

Hello
I had a 36 weeks scan last week. These are offered at my trust so I wasn’t sent due to any growth worries or abnormalities found.

At 20 week scan everything looked good with Femur Length on the 8th- wasn’t mentioned and I am short (5ft1) so was not worried. All the men in my family are also short.

This week all looked good with growth patterns in comparison to the 20week scan but femur length was 56mm which is completely off the chart and below the 1st centile. The sonographer said she wasn’t worried because it is still increasing and following its own line. However after looking up on google it seems like an incredibly short measurement and weeks behind?!?! People on these forums worrying about measurements much higher than mine. I probably wouldn’t have googled but as we left she said ‘just because someone has short femurs doesn’t mean they are going to have dwarfism’ and of course I had a panic. She didn’t refer me and I was not expecting it and didn’t ask any questions! Can’t get hold of my midwife so called the MLU and they just said if she says it’s fine then don’t worry. I just feel like I want someone to sit down with me and go through possible outcomes here?

Has anyone else had this? How accurate are these measurements? I am now beside myself with worry and actually don’t know how I am going to get through the next 4 weeks and birth.. I have not been well during this pregnancy (sickness/reflux) and feel like I have done something wrong :-( if there is an abnormality then I know I cannot change this now but I feel like the unknown is stressing me out for birth. I am just praying the measurement was wrong as it just seems so far out?

Thanks for any advice/experiences

The scans are rubbish.
At 20 week scan I was told that DD FL is below 4th centile and it was being confirmed after (had to have scan every 4 week until 36 weeks).
They said it may be an indication of DS (they picked up on a fact that I refused prenatal testing and found it so mean as I said, repeatedly that I do not mind and won't do anything about it anyway).
I am 5'4" so not tall at all, and females in my family tend to be even shorter.
She was born fine,no one measured her legs after birth and now she is pretty tall 4 year old.

I think it's agreed there's a 25% error margin.

Most importantly, the medical professionals aren't concerned.

Step away from Dr Google (I mean this kindly) - getting worried about something that's nothing to worry about is not a good path to go down.

I sorry to hear that you are going through this. I am going through something very similar so can't offer any advice but wanted to share. On Saturday had a growth scan as the baby was measuring small and we were told he was small in weight and had a short femur. He was on the 7th centile and had dropped weight since the last scan (previously on the 17th). The Dr also wasn't concerned. Initially said he would refer to fetal medicine as it was procedure but then spoke to them and they decided, as I am having a c-section with another scan next Tuesday and an appointment with my consultant anyway I should speak to them then.

Can you speak to your midwife?

Obviously you have been googling as I have and short femurs are soft indicators for genetic problems so we are really worried. But the logical side of our thinking is this would have been more likely to have been picked up by the initial screening and 20 week scan.

I have also had sickness throughout (morning sickness, stomach bug and food poisoning for 10 days at 22 weeks!) together with reflux so I wonder if there is a link? The Dr did say that there wasn't (I asked) but it's difficult not to look for answers.

@3JsMa @crispywaffle thanks for your messages! I think I need to stop googling you are right. I do deep down feel like the measurement must be wrong... I only have a 36 week scan because it’s routine in my hospital (part of a trial maybe?) if I was living in a different area then I would just be plodding along (waddling ) getting ready for birth!

I think I am most scared of the unknown. Which actually I should probably get used to if I am going to become a Mumma!

@Crazycatlady83 hopefully we can keep in contact and provide a bit of comfort for one another! I feel almost more stressed being told not to worry! And not yet as I haven’t been able to get hold of her (which made things worse) will be trying again tomorrow!

Good luck next week

Had the same worry and looked everywhere for answers but couldn't find anything reassuring.
Those measurements are rubbish i confirm.
My daughter was born perfectly normal with standard baby proportions!!!!

Please try not to worry yourself... if your sonographer and MW aren't concerned then it's ok! As my MW told me at the time... babies come in all shape and forms just like us! And those scans are not very accurate especially towards the end when the baby gets bigger.

Thank you @Helloitsmi I think I’ve just really convinced myself something is out of the ordinary. Even though most people I know say the 36 week scans aren’t accurate. I’m not consultant based either so I guess even more margin fo error!

My 36 week growth scan was very accurate regarding measurements and weight. Some are, some aren’t. If your sonographer wasn’t concerned and didn’t refer you, I wouldn’t worry.

@Bobbysmumsy good luck with contacting your midwife. I spoke to my midwife today. She was confused about the advice of waiting to speak to the consultant (which has only been booked for my c-Section rather than anything to do with the baby) so she went to speak to the fetal screening midwife who will take my scan to fetal medicine herself. She also spoke to the sonographer who scanned me who said there was nothing else to worry about in my scan (he looked like he lost weight because of his short leg measurement only) so that's good news. Just got to wait for the fetal screening midwife to call me now which will apparently be a few (nervous) days to see if there needs to be any more next steps.

@Crazycatlady83 I ended up emailing the ultrasound dept. explaining my worries and asking if I could have a phone call with someone to go over my notes. They called me back saying they are worried about how anxious I am and have given me a scan with FMU tomorrow to put my mind at ease... so I’m feeling better I think! She didn’t say it was to do with any issues with my notes so sounds like they just want to make sure I’m not stressed!

Glad your midwife chased up for you! Hope you aren’t too stressed.. I know how it feels!

@Bobbysmumsy so glad you managed to get another scan with the FMU. Hopefully their detailed scan will give you more reassurance. Good luck for tomorrow

@Crazycatlady83 just got back.
Turns out that the scan image from last week shows 67mm but the sonographer wrote 56mm instead.. completely skewing all my charts and graphs! She showed us the scan image and measurements.
Then she measured him again today and femur is 70mm and bang on the 50th with him now being 50th overall! Please let me know how you get on too

@Bobbysmumsy that's great news! I can't believe a typo has caused all your concern - how frustrating for you! But relief as well! I spoke to the foetal screening midwife today who had taken my results to the medicine unit. They said there was nothing to worry about - he is just following his "own" line (which he has been on since the start) for his head, stomach and legs. I am keeping my appointment with my consultant (it's for a c-section anyway) and if she is concerned, they will scan me again but the FMU weren't concerned.

@Crazycatlady83

Yay! This is also great news- super pleased for you! How long have you got until your c section?