Worried about Femur Length - 2 weeks behind?

[evwAnxious]

Hi,

I’m hoping someone can help provide me with some reassurance. As of today, I’m 27 weeks pregnant. If all goes well, i’ll be a FTM however this is my second pregnancy. Due to my lower BMI, I’m having to have regular growth scans, I had my first one yesterday at 26+6.

The sonographer was lovely, the baby’s head is in the 78th percentile, his stomach is in the 60s I think and his overall weight is just shy of the 50th percentile according to the sonographer. However, and the reason I am so worried, is that his legs are two weeks behind and are on the 5th percentile. The sonographer said its just something to keep an eye on and that I shouldn’t be worried and at the moment there is no need to be sent to the FMU. I’ll have another growth scan in 2 weeks and she said likelihood is it’ll have balanced out by then. I am quite an anxious person usually and have always just been a worrier. Baby never makes it easy at scans and is always in a dodgy position/regularly wriggling around.

This just really knocked me and when you look up about short femur length all sorts of risks come up such as Down Syndrome and Dwarfism. I’ve had the NHS screening and private Harmony test and all came back low risk. I’ve been in absolute bits ever since and feel miserable. My midwife and fiancé have reiterated the same reassurance but I just cant shake this all consuming fear that at the next appointment things will be worse and we’ll be sent to FMU for an emergency appointment.

I’m probably being irrational, and I know I’ve already had plenty of reassurance but I just wanted to hear about anyone else who has been through this and to see if everything turned out okay? I’ve read similar posts but people dont seem to provide an update. Anyway, thanks for reading xx

Hey, I just saw this as I popped back in to update a thread I started a couple months ago on femur length. Just linking here in case it's useful, as I got a lot of positive responses www.mumsnet.com/Talk/pregnancy/4405672-growth-scans-low-femur-length

I was all over the place as well and very worried. I'm 35 weeks now and they don't think there are any issues as they've been growing along a curve, and have increased slightly to 8th-10th centile - at one point they were measuring 3rd centile. We did see a FMU specialist who examined all the bones and the skeleton. They said if it was dysplasia they would expect to see narrowed rib cages, potential issues with the spine, bowing of the short bones, and frontal bossing of the skull.

I had a private NIPT also, and they seemed to think genetic issues were pretty much ruled out as a result.

It's so worrying, I honestly read everything I could on it for weeks, including a lot of studies. And I cried a fair amount. Hopefully you get some good comments from more experienced people

Also, do you know what the femurs measured at your nipt scan and the 20 week scan? They plotted mine out for me in a chart, and I realised that mine had always been a bit on the shorter side. They told me a bigger drop is more concerning, but if they've been consistently shorter then it's more likely to be a constitutionally smaller baby

Hi,

Thanks so much for replying, I really appreciate it and I'm glad to hear youve been getting some good news !

Honestly I've never felt so scared.

I dont have exact measurements for fetal length I just got the percentiles. At 20 weeks, they said it was a little small but still normal and it was the 16th percentile, now its 5th percentile so do you think this would constitute a big drop? xx

My, now 11 year old, son had this mentioned on a scan. He is now taller than me! I would try not to worry.

Enjoy the rest of your pregnancy x

Hi I'm in a similar situation. A few weeks ago I had the '20 week' scan (I was 19 weeks 3 days), my baby's head and abominal circumference was around 70th percentile but the femur length measured 'off the chart', below the 3rd percentile. I've been so worried and have had to wait over 2 weeks for another scan to check the growth. My scan is tomorrow morning. It is such a worry :( if the femur length is still short I'll be referred to a specialist, but I hope it is just a mistake or something.

Oh I'm so sorry to hear that. I've got my fingers crossed for you tomorrow. If you feel up to it, please let me know how it goes xx

@evwAnxious I don't think that sounds like a big drop, mine were varying but always in the lower quartile, so they seemed to think that was his growth line. At 5th centile, he's still measuring normal. A growth scan in a couple weeks will hopefully put your mind at rest.

@Xxdxx2020 good luck for your scan tomorrow. For what it's worth, I was sent to FMU after one of my growth scans as I was below 3rd centile also (and v v worried also) They were really thorough, measured everything, and examined the skeleton. Short femur in isolation doesn't seem to be too much of a worry for them. So feel positive about tomorrow

Hi, I had my scan today at 21w5d. It is good news so far, the baby's femur length has moved from below the 3rd percentile line to just on it (it is either 3rd or 5th percentile, not sure). I spoke to a consultant afterwards who is not concerned at all, she said this is now in the normal range (just!) and there are no other abnormalities, I was low risk for DS, and the abdominal circumference is now in 87th percentile which indicates no growth restriction. I will have a rescan for reassurance at 28 weeks, but I have been reassured this baby is just a short one and nothing concerning xxx

@Xxdxx2020 That's really fantastic news, so happy for you!! Must be a huge relief. The 28 week scan will be lovely to see baby again

Oh, that's brilliant news! So happy for you and baby!

My little twins femur length was 2 weeks behind - so low her legs didn't even chart - lower than the 1st centile - I also had low risk NIPT etc.

I had fortnightly scans as she was measuring half the size of her brother but the doctors said she was just growing at her own pace and so long as her growth was consistent then they had no concerns. Also babies apparently grow head down which is why head and abdomen centiles tend to be higher than leg ones. My little twin was born early but healthy - her legs are still little but not noticeably so to anyone other than me and only when you put her side by side with her twin

Also they only tend to worry if the leg length is low compared to other ratios - can't remember if it's leg/head ratio or leg/abdomen - my little twin was just on the threshold below which could Have been an indicator for downs etc

Hiya OP,

FL is the most inaccurate of all the measurements to estimate fetal weight, in fact some hospitals don’t even use it that’s how inaccurate it is.

I had growth scans as my first was born small, and at my 35 week one baby’s legs were just under the 10th, the midwife who scanned me wasn’t bothered at all. Fast forward to birth, little boy was nearly 52 cm long. He’s 4 weeks and grown out of up to one month clothing so is over 56cm long, so around 75th centile. My point is, the FL measurement is v inaccurate, it’s the EFW they tend to look at, even though for a lot that can be quite inaccurate too xx

Hi OP, Just wondered, how things have progressed for you and your little one?
I got similar news today - I'm now at 27 weeks, and was told the femur had dropped from 76th centile to 6th centile.
You must be getting quite close to your due date now. I hope all's well.

Hi, this is pretty much exactly the situation I am in. How did things turn out?

Hi!

My baby boy was born at the end of March and honestly everything was fine, he is just a small baby and takes after his Dad's side of the family in height. His legs and arms are small and his sleepsuits are a little baggy in those areas but he's completely normal.

Looking back I wish I hadn't worried as much as I did. What I will say is that these scans aren't totally reliable, his weight for example was completely different to what they said a week before his arrival so try not to worry too much.

Thanks so much for the reply, really pleased to hear everything turned out ok. We don't have much height between us (I'm 5'4 and my husband is 5'8) so hopefully it just means she is going to be a small baby.

For anyone following this in search of answers: My baby was born, the cause was a marginal and velamentous cord insertion, diagnosed after delivery, causing growth restriction. He is perfect and healthy, fitting into all this clothes as expected, and developing perfectly. Such a stressful time but I'm forever thankful that he is here and healthy.

I had this. They started asking me and my husband how tall we were mid scan!

My son is second shortest in his year and has a fairly long body compared to overall height but he's perfectly healthy. I now realise he takes after one of his great grandads!

I'm short ish. Husband is average ish height.

Oh and his head size was and still is 90th centile!

(He looks perfectly fine. Adorable if I do say so myself).

Try not to worry. It's good that you are being monitored but it's most likely fine.

Just realised this is an old thread.

So glad babies were ok too!