femur at 5th centile, head circumference over 95th centile... is this 'normal'?

[WhatAHooHa]

Bit of a backstory first... DS was born 2 years ago with a congenital heart defect which required major corrective surgeries, ongoing treatment and possibly future surgeries for complications.

I am pregnant again now (25+4 weeks) and really struggling with anxiety, I think, so I am aware I may be reading something from nothing.

DS' cardiac consultant tells me that his condition means that there is a higher chance of future children also having cardiac problems, so we should be given additional scans to check. My obstetrician refutes this, saying we do not need an extra scans. Looking online at various NHS sites, it does seem standard to offer people in my situation additional monitoring but it seems to be a budgetary thing here (Wales). They also don't do the quad testing here (triple test only), no nuchal fold testing etc. My triple test results came in at 1:350, compared to when I was pregnant with ds', when it was 1:7300ish; I had a bit of a panic about this at the time but talked myself down by thinking about the odds more rationally rather than just comparing to previous pregnancy.

We scraped together the money to get a private cardiac scan, which we had today.

Today's scan showed the heart to be fine (relieved face) but did throw up some measurements which I feel I need reassurance on...
Head Circumference 256mm - over 95th centile
Abdominal Circumference 216mm - around 75th centile
Femur Length 42mm - just scraping 5th centile.

The sonographer seemed a bit rushed when we came out and just sort of said "it's all fine, all in normal ranges, no worries" and saw us out the door. Which may be the case, but the disparity between the HC and the FL being at the very very limits of those ranges seems quite marked? I have heard that a short femur can be a soft marker for Downs? Do I need to follow up or am I just letting my anxiety getting the better of me? I kind of feel like everyone so far has just been quite blasé about my worries and I can feel myself working my way up to panic stations again!

Thankyou for reading all this!

[Pizdets]

Hi WhatAHooHa, sorry to hear you're so stressed. Not exactly the same but we had a tmfr in 2012 for a rare chromosomal problem and in the subsequent pregnancy I didn't know what to expect! At the 20 weeks scan DS' measurements were all over - some below 20th and others above 70th. Like you I raised it with the sonographer and was told 'all normal' and ushered out of the door, I went home in a complete state.

I'm in no position to tell you anything definitive but DS was born last September and is absolutely fine. In fact we had a scan at 34 weeks which placed him on the 50th centile and when he was born at 40 weeks he was 9lbs 4oz (97th centile) so I don't put too much faith in scan measurements any more. However I would say that if you're worried you should push for feedback at your hospital to give you peace of mind. Is there a genetic counsellor you could speak to?

I know it seems like you're being a pain but they should be helping to give you peace of mind and you are within your rights to make a bit of a fuss! It's not a nice way to continue your pregnancy if you're going to be worrying.

Hope you get some reassurance soon.

Piz

[diege]

As someone who works in screening I don't think you have anything to be concerned about. The short femur as a soft marker of downs is, in isolation, pretty meaningless and is discounted when everything is 'normal'. The disparity between percentiles for different measurements happens a lot, and you may well find that in another 3 weeks the femurs would have 'caught up' (and the hc slowed).
On a personal level, I've had the very same thing as you with 3 of my 6 dcs. The last 2 in particular had hc as 90th pc, and femur at 8th percentile, mirroring dc 5. Dc 1 too had femur off the scale (ie, shorter than the charts, head 75th). She is 13 next week and has both a big head and long legs now! You can drive yourself mad with googling, but you would actually find if you look at some of the most up-to-date screening docs (antenatal screening wales doc is good) that an isolated 'short' femur,(in relation to a 'large hc) is meaningless in terms of marker for anything.

[CrispyFB]

My four children have all been mostly around that, especially DC1 who had similar numbers. I just seem to make babies with big heads and short legs.. like their mother (I seem to need large hats and even short leg length trousers don't always fit!)

Even if it's not the case for you, there is probably something in the genes on one or both sides to make a baby this way.

I'm sorry you're having such a stressful time and it's a real shame they couldn't reassure you better than they did given your history.

[WhatAHooHa]

Thank you all for your messages, was just what I needed to hear! I know I need to just relax and enjoy this pregnancy more but can't help preparing myself for bad news it seems, never realised I was such a pessimist before!

My Dad's side of the family do all have very short legs, and thinking about it my mum does aways have trouble finding hats that fit so perhaps the combination of grandparents genes have combined here...

Right, determined to be more optimistic from now on and hopefully start bonding with this baby a bit more!

Thank you again for your support

[Mamami]

Hi,

I came on to write my own post and found this one.

Last night I went for a private 4D and growth scan as I didn’t have the bump I expected at 30 weeks (turns out I have an anterior placenta – probably the cause). The scan was quite cheap and the place seemed a bit rubbish.

Anyway – growth scan showed she’s fine. Right on track with everything – except her head side is in the 97th percentile and her femur length is in the 13th. The sonographer just said ‘she’s great’ and printed off the report so I didn't realise until we’d left and headed home. Confused, I hit Google and have now freaked myself out.

I’m over 6ft – so I doubt my daughter’s just going to be short. Also her head size seems a worry when the rest of her is all around the 50th percentile. Again, the private sonographer didn’t seem worried. She just didn’t talk us through the report at all

I'm panicking. After a late loss last year, I've found I'm constantly waiting for the other shoe to drop this time.

But reading your post and replies has really helped.

So - you're not alone. We'll try not to be too worried together.