Short limbs at 36 weeks scan

[Mim78]

Wondering if anyone can help.

I've just had a scan at 36 weeks because the hospital had been concerned the baby was small (10th centile). He has now slipped down to below 5th centile- he is growing but not at the same rate.

What concerns me is that from looking at the measurements I can see that while the head circ is 28th centile (made up of 40th and 24th) and the abdominal circ is 24th centile (so proportionate to one another) the femur and humerus lengths are below 5th centile.

The doctor did not point this out to me at the hospital - I noticed it afterwards. Presumably she would have mentioned as a cause for concern. I am now worried about achondroplasia (dwarfism) and to a lesser extent downs (because I have had a negative harmony test already).

Does anyone have any experience of this?

Clearly, despite all advice, I've googled like mad. I'm coming up against the idea that if achondroplasia was likely the head would be big rather than on the small side of average aswell, which would be reassuring if correct.

DD1 was small at birth (but not as small as under 5th centile). DH and I are quite small - he in particular has quite short limbs, but doesn't have achondroplasia.

Are you in the uk? Why did they measure the arm? This is generally not a routine measurement unless there is a concern in my practice.
The usual measurements are ac (abdo measurement) hc (head circumference) and fl (femur length) the ac can be quite variable due to stomach size and fetal position. Was baby low down in your pelvis? That can affect the head size.

It's worrying hat the dr did not point talk to you about the femurs being under the 5th centile. How tall are you and your partner? If your of shorter stature they may not be too worried.

Yes we are in the UK - we are at UCH and I know they do more scans and include more measurements than other hospitals. For instance I had a 32 week scan as routine. They have been measuring the humerus all the way through I now notice - it has been pretty small all the way through but this is the first time it has slipped below the 5th.

They didn't point to the femurs being under the 5th - they are above the 3rd though which seems to be of some significance in the graphs they have provided and in the internet research I have done. The humerus is now the lowest measurement.

The head is low but then again the head measurement was normal. It has been about 24th centile all the way through although at one point (20 weeks) the bipariental diameter was low - hovering over the 5th centile but that equalled out in the circumference measurement.

I am 5'5/6 ish and partner is 5'8". As mentioned he does have short legs - both my family and his have short legs for our height - even my Dad who is the only source of tall genes (5'11") has short legs (wears 30" trousers I know). My Mum has very short arms and so did her Dad - dh tells me his arms are short when buying jackets etc.

If it helps, they scanned my daughter at 36 weeks and went into panic mode because they thought her head and some of the other measurements were off the scale. They rescanned at 38 weeks and she was smaller than at the 36 week scan, and then when she was born they found she was completely normal (50 to 75 centile).

I think sometimes the scan measurements can just be really inaccurate? x

They did have a slight error with their machine not transferring measurements and then had to do it by hand, so I guess there could be room for error?

Thanks to both of you though!

Anything above the 5the centile is normal. It can be hard to get accurate measure bra at this stage, what their really interested in is if there is fluid around baby and the cord Doppler.
Is there a fetal med unit attached to uch? Is that why they measure arms.

My DD's head is massive - was at her scan and still is 2 years late. (currently 98th centile head vs 2nd centile weight/height).

Honestly I wouldn't worry. You can drive yourself mad looking at the stats but you yourself said they've ruled out dwarfism.

We're not all perfectly proportioned. I have a big head, as does my DH but plenty of friends have smaller heads. That's life!

When I was in hospital with unstable placenta praevia with DC3 my assigned consultant waltzed in and announced (with my mum and DD1 in the room, DH not present) "that the baby's legs were too short and might be disabled. But not to worry, my CS was planned for 2 weeks time"!!!!!!!!!

Once I had got what she was saying into my head I demanded that a doctor came to speak to me. A junior doctor arrived, couldn't answer my questions.. She arranged for another consultant yo come and talk to me. (Incidentally, this lady, who was not my consultant, had a particular interest in my condition and had seen me more than my own assigned consultant and arranged loads of tests, got me seen at another hospital by a specialist who was doing a study).

The second (lovely) consultant came to see me, with my scan, the scan from the other hospital, she plotted the other scans measurements onto the graph, asked me how tall DH was (only about 5'6" and short limbs) and advised me that although the measurement of the baby's leg was slightly below average, it was following the same curve so she wasn't worried.

DD2 was absolutely fine.

When they are clicking the mouse onto the screen there is a risk of human error, whether they click on the inner or outer end of the bone.

I hope everything will be ok.

Glad I found this post. I am pregnant with my third baby. In Nov time time results from the Quad test indicated that I had a 1:5 risk of DS, Harmony test came back as normal. I have a two vessel cord so having additonal scans for this. I had a private 4D scan last night with the Consultant who did my Harmony test. He said everything was great and he was not concerned about the baby at all, however, when I reviewed the measurements BPD measuring at 32 weeks 6 days, HC 32 weeks 2 days, AC 33 weeks and the femur length is only measuring at 28 weeks 2 days. I am currently 30 weeks pregnant. The AC is at the 97.7% and some 5 weeks ahead of the FL at 3.5%. I am really stressing out about this help!!!!!!!

Hi everything crossed. really hope everything is fine for you. If consultant said everything is fine then that is a really good sign. I haven't been back for my next scan yet (it's on Wed) but will update you when and if I find out more about what this all means!

Thanks mim78, keep me posted, I am due at the hospital again on the 18th will let you know how I get on, good luck for Wed x o

Hope all goes well for you, EverthingcrossedforApril14. My baby’s FL is a bit on the short side too (I’m also waiting for NIFTY blood test results as my quad test results indicated a higher than my age risk, so I’m analysing all my measurements to death on the dreaded Dr Google), but the consultant said to me that anything below the 3rd centile is when they start to look into FL being ‘small’. So, hopefully you can take some comfort that your FL isn’t ‘significantly clinically’ small, hence your consultants confidence. Great news on your Harmony result too . Good luck for the 18th. X

Mim78, best of luck for Wednesday. I keep being told by lots of people (professionals and friends who have had babies) that babies’ measurements can be all over the place and they all grow different parts at different rates. I hope you get the reassurance you need on Wednesday x

Thanks to both of you. x

Hello

I thought those who have replied, and especially those encountering similar problems, would like to know that I have had another scan today and have been told:

1. it's not downs because I've had the harmony test and apparently this is more accurate than they let on. Also there are no other markers apart from shortish limbs.

2.It is not achondroplasia or any other for of dwarfism (sorry if this is un-PC term but I don't know all the names) because limb measurements would have plateaued rather than continuing to grow on 3rd/5th centile, and this would have happened at a much earlier stage, and the head would be much bigger.

I had generally good news in that the growth has improved since last time. The arms and legs are still on low centiles (5th ish) but apparently this is not a concern in itself as they are growing steadily as are the other measurements.

Hope this is also reassuring for those in similar position.

Great news mim .

Scan sizing is inaccurate. I was scanned a lot with my twins. I was told both were a really similar size, only a few ounces apart, til my 34 week scan. Then they said one baby's head circumference hadn't grown, the other baby's abdominal circumference hadn't grown. They said that meant there'd been a scan error as head growth is preserved over everything else, but booked a placental doppler due to the low ac on twin 2. Then assured me all fine, twin 2 still growing- yet a week later he was born a full lb lighter than his brother. I think he may well have stopped growing!

Yes - they thought they had made some slight mistakes last time as it was a dip in the graph, but apparently arms and legs are easier to measure than head and abdominal circumference.

Great news Mim, my babies FL has grown since the 20 week scan but not as much as the other bits and bobs that they measure. FL was measuring similar to other parts at 20 weeks and 5 weeks behind at 30 weeks. I will try not to worry and wait until the 18th to see what the Consultant says about it. I am in the same positon as you with a clear Harmony so was mostly worried about dwarfism (like you said sorry if this is not the correct term). I was speaking to a friend about it and she said a few mm's could make a difference and the posiiton of my baby at the time of the 30 week appointment may have made it difficult to measure. Glad you got so answers and some reassurance! x

with my 2ds I was scanned lots at the end and pressured to have inductions and c sections because, according to the scans, they were massive (10lb in one case) and I am only 5ft. In both cases they came out pretty average (8 and 7, 13) but have big heads. Their brother who was normal throughout was much bigger at birth. All fine.noy sure the scans are that accurate at the end

They did say the scans not accurate at the end.

I'm thinking if he's 6 lb 2 now though he might end up quite big!

I'm happy to be induced a day before due date though (current plan) as I'm a bit of a control freak and it went really well last time.