Nasal bone absent at 11+5

[Elpis]

I know this post may seem overwrought to mothers who have been given a much higher risk of Down's, but I can't push this out of my mind.

The tests put my risk at 1:4092 (even lower for the other trisonomies). Since I'm 36 we weren't worried about that. But the sonographer couldn't find a nasal bone. She said this was unlikely to be significant because I was less than 12 weeks and didn't recommend an extra scan.

At my 20-wk scan the nasal bone was present and 5.7mm long - I think the average is 6.2mm, so on the low side but still within normal range. Everything else was normal - a 'perfect little boy', said the sonographer. So why am I anxious? Because I saw that lack of a nasal bone at 11-14 is a 'soft marker' for Down's. Some researchers think it is a stronger marker and ought to be part of the overall test. I know the testing doesn't always spot Down's. It seems 65%+ of Down's foetuses don't have a visible nasal bone at the nuchal scan, compared to 1-3% of normal foetuses.

I can't stop fretting about this now. I realise it's probably hormonal in part (I'm 22+3) but can't seem to stop. It's too late for the invasive tests which I might not have wanted anyway.

Why do we have to go through this? I'd never have thought about it if it weren't for the abundance of information so easily available. DH, a rationalist, isn't alarmed. I wish I could pull myself together.

[Elpis]

Oh, wonderful. Happy new year, secondsop! DS is very plump and has just started teething.

[Secondsop]

Hi elphis congratulations on your son and thanks for the update. I found this thread really helpful so just wanted to update to say that my son was born on 29 November with no signs of abnormalities and a perfect little nose, but I would love him whatever happened. Thoughts to freshfruitsalad and thanks to you elphis and to everyone else who commented.

[Elpis]

So glad to hear that. He sounds lovely. DS is very good too and only seems to cry when hungry or in discomfort, which is marvellous.

[freshfruitsalad]

Very well, his health is very good so we are lucky :) he is lively, strong and so well behaved, doesn't cry much at all! I have been counting my blessings

[Elpis]

Thanks freshfruitsalad! How's it going?

[freshfruitsalad]

Oops forgot.... Congratulations xx :)

[freshfruitsalad]

I love my little boy; more so I think as just so proud of him. Thanks for update elpis xx

[narmada]

Congrats - enjoy him. They grow so quickly :)

[Elderflowergranita]

Lovely update Elpis. Congratulations!

[Elpis]

Just to update... I now have a lovely two-month-old DS with no sign of any abnormalities. I would love him just as much if he had Down's and am thinking of freshfruitsalad. I hope anyone coming across this thread is reassured.

[somewherebecomingrain]

OP my DS had no nasal bone at our 12 week scan at the FMC (the NHS didn't do one!!!! its equipment broke!) and a 1 in 3000 chance of Downs. they said no nasal bone is more common in black children which was interesting but sort of by the by for me as i'm not black. but i was really pleased with my estimated risk. Aged 36 i thought it was a good result. My boy came out without downs in the end.

[brettgirl2]

I read it was because you have to add the 'absent nasal bone' numbers to 'unable to see clearly' numbers. This is up to 5%. Therefore it has the potential to lead to a lot more false positives and unnecessary invasive testing and worry.

The nuchal and bloods alone already has a ridiculously high false positive rate. Worrying even more women half to death about absolutely nothing is not seen as a benefit as far as NHS is concerned.

From what I understand the FMC looks at several other factors too and therefore keeps the nasal bone more in reasonable context.

Please try to relax op the vast vast majority of babies are chromosomally normal and the results show that yours is highly likely to be one of them.

I wonder what the probability is of being run over by a bus?

[Secondsop]

Thank you littlepoot x. Interesting to hear of a hospital that no longer factors in nasal bone.

[LittlePoot]

Another downs baby here with a perfect nasal bone at the nuchal scan, along with a huge nuchal fold. I don't think its so much that the nasal bone factoring will be rolled out into use everywhere-at our hospital, they used to factor it in but now don't because it's looking less and less like a reliable marker. x

[Secondsop]

Ah, thanks sleepyhead. I should have been able to work out 1:50 as a percentage really shouldn't I ...

[sleepyhead]

Ok, so they reckon that, statistically, 98% of babies with no nasal bone seen at 12 wks will be chromosomally normal and 2% will have DS (taking no other factors into account, which of course they wouldn't do).

I hope all goes well for the rest of your pregnancy

[Secondsop]

Thanks sleepyhead and wipsglitter for your comments. Kings gave a 1:50 weighting for absent nasal bone (so my overall weighting was 1:130 once the bloods and everything else were factored in).

I shall do my best not to worry - in any event this baby is much longed-for; it's my lack of understanding of the numbers that has thrown me a little.


I forgot to say Elpis great news about your 33 week scan and good luck with the rest of your pregnancy!

[sleepyhead]

Secondsop - 1-3% of chromosomally normally babies having the nasal bone absent at 12 weeks is not the same thing as saying only 1-3% of babies without a nasal bone at 12 weeks are chromosomally normal!

I don't know what sort of weighting Prof Nicolaides gives for the nasal bone in the overall result, but he's certainly not saying that absence gives a 97% chance of there being an abnormality, so the stats aren't as worrying as you're seeing them.

[WipsGlitter]

Nasal bone is, along with nuchal and bloods, not a definitive test. My son had downs but also has a beautiful nose with a bridge! Try not to worry.

[Secondsop]

I forgot to mention: my scans were at King's, and the FMC use the same sonographers, which would explain why the nose was factored in for me. It would be interesting to see if the nasal bone measurement becomes more universally established.

[Secondsop]

Elpis thank you for your comment. Yes, I also understood that the Fetal medicine centre pioneered the research into nasal bones and Down's but it's very interesting to read what you say about the studies possibly being in high-risk populations. I gather there's a bit of a battle of the papers about the significance of the nose, and also that ethnicity can play a part, especially for non-caucasians (of which I am one). The nasal bone also seems to be a pretty new test - I can't find much about it from more than about 4 years ago.

[Elpis]

secondsop I too am confused about why some hospitals factor in the absence of a nasal bone and others don't. Mine (UCLH) is one of the leading London centres too. All I can gather is that a leading light at the private Fetal Medicine Centre has been writing a lot of papers about a link between absent nasal bone and Down's. Now, it seems to me that any survey carried out among FMC patients would have a higher rate of abnormalities, because they are more likely to have come there because of concerns and because they are likely to be older and richer. This research may well be right. But I know not everyone has accepted it yet.

I do hope all will go well for you. My 33wk scan was normal so I'm hoping that this means we're in the clear, although I know some cases of Down's are only diagnosed after birth.

[Secondsop]

Hi freshfruitsalad thank you for sharing. Perhaps your scans showed
a larger nuchal fold measurement which I gather is a better indicator than nasal bone? Or it may be that your hospital is one that doesn't factor in the nasal bone at all. thanks again for sharing your experience and I hope all goes well with the rest of your pregnancy.

[freshfruitsalad]

We have done all the testing and confirmed for Down syndrome, now at 34 weeks nobody has ever mentioned nasal bone one way or another and we have had loads of scans, wonder why when we came back high risk, they didn't check our measurements

[Secondsop]

Hello, just found this thread which is similar to my thread about nasal bones. My baby's was absent at 13+5, and 4.7mm at 22 weeks (cut off for normal = 4.5 so he's JUST within the range), and my risk at 13 weeks was 1:130 (it remained the same at 22 weeks). So your numbers are an awful lot better than mine! I'm 36 and it was the nose that made the difference to my numbers (the sonographer showed me the graph had there been a nasal bone and it was wildly different). So it does sound like it was the fact that your scan was at 11 weeks that meant that your numbers are actually very favourable.

I hadn't seen the stat about only 1-3% of babies with absent nasal bone being chromosonally normal, so it's worried me somewhat. If that's the case i wonder why my numbers arent even worse? I wonder whether babies with absent nasal bones often have other markers, which mine doesnt, and whether that is what brings my numbers to
1:130 rather than the much higher percentage that the 1-3% stat suggests. I guess all I can do is have my late amnio (I declined a CVS or amnio at 13 weeks because the miscarriage risk was higher than my Down's risk, and I knew I'd be continuing the pregnancy in any event. Am 24 weeks now). My other soft markers were all fine and the bloods etc, and the anomaly scan didn't show up anything wrong with the baby's heart so hopefully even if he does have Down's hopefully no other major problem has been indicated.

OP , have you managed to find out any other information about the nasal bone? I understand ethnicity can make a difference, and I also understand that some hospitals don't factor it in as a marker at all.