Back from nuchal fold test. Confused.

[Har]

Hi.
I've just come back from my nuchal fold ultrasound and I am a little confused by my results.
During the ultrasound the measurements were made and the result was 1.1 which is apparently good. The risk for my age (27) was 1:806 and this decreased greatly once the nuchal fold measurement had been factored in. However once the blood test was factored in the risk rose to 1:420.
I feel that means the blood results must have been very bad to make such a difference.
In Sweden (where I'm living) you only continue testing (with amnio) when it's 1:250 but I talked to a friend in England who said that in UK it's 1:400. That means I must be pretty close to the risk zone.
The sonographer and midwife told me it was nothing to worry about but I don't understand. Something is showing up if the risk rose like that. What is it? Sorry if this doesn't make sense, I'm not really sure what I mean myself. I understand that it's still a low risk and I don't mean to be insensitive to those who have very high risks, but I am just a bit confused.
Would really appreciate if someone could clarify this for me. My Trisomy 18+13 went from age risk of 1:1428 to 1:8332 by the way. That that was so good makes me more concerned about Trisomy 21.
Thank you and sorry for waffly post!

here it is 1:250, not 400.

you are still low risk - the midwife would have told you if there was any concern. the measurements are based on your age, the babys age and certain other measurements, not something showing up to increase the risk iyswim?

I don't know about the bloods but I was told anything under 3mm is fine - my second baby was 2.2mm and is Ok. hthab x

Thanks Scorpio. Understand the age, baby's age, and measurements etc, it's just that with them all factored in the risk was very, very low and then when the blood was factored in it rose a lot. Good to know that my friend was muddled about the 400 thing though!

Har - from what I've read the high risk group is when the result is 1/250 and that seems pretty widespread. I wouldn't worry too much , at least your baby co-operated eh?

Deb

Thanks Twinkly, is the blood not tested in England? My friend said her NHS trust didn't test. Would have been so happy with my 1.1 if not for the blood!

do you know the number from your blood test alone? i bet its just a combination of things, rather than one individual test iyswim?

with all 3 of my pgs i have had just the bloods done, and each time got 1:5000 or less.

Great your baby is ok Twinkly btw!

Deb, took a while though! Wrote in our ante-natal thread that i had to bang my body down (like those 'bridge' bottom exercises but bang at the end, sore cocyx now!) hard a few times to get him moving. Felt so mean! Curled up onto its tummy, sucked thumb, the works!

Scorpio, unfortunately don't know what the result for the blood test was on it's own. Just have the end result printed out.

don't worry. it is still a low risk by any means, well over the point at which they worry. you have to remember what a small percentage chance that is!

Are you worried enough about trisomy 21 to get further tests? i just mean if it would be a concern to you, everyone is different.

Thanks Scorpio. No I don't think I'll take any further tests, I don't think the mw would let me tbh. I know I shouldn't worry and the result is still low, it's more that I don't understand why. Talked to my mum and she said that she thought the neck measurement was probably the most important/obvious and that what the blood test showed up could be a signal of something that could equally mean something else ie (and this is completely made up, apologies for anyone scientific reading) a high level of a vitamin or something in blood coupled with high neck measurement could mean something, but on its own could mean something else (not scary!) Would this make sense? (Sorry what I've written certainly doesn't! Just want to know what in blood it is that changed my results).

It sounds like the systems are very different between the 2 countries. Blood tests (when given) here would take place later so presumably its a different test.

You may be able to ask for a more detailed scan at some stage. Is there a midwife you could ring to ask to explain it to you?

the blood test (I believe) is fairly dependent on the gestation being totally accurate - ie if the sperm lived for days prior to fertilizing egg etc, you might be a few days adrift, or if the cycle you conceived in was not perfectly regular etc etc. If I was you, I would forget about it totally, try not to give it another thought and enjoy your pg.

Hi Yurt, asked my midwife (had my appointment with her later in the day) but she said she didn't really understand how it worked herself, great! As for the blood test, it's testing the placenta and the baby itself (though how from my blood I'm not sure, and for what, again I'm not sure). Trying to get hold of my brother who's a doctor and explains things well (and slowly!) but his phone's off.

Off out now, thank you so much to everyone who's helped so far.

Here's something from a website:

When a woman is offered a nuchal translucency, she will also be offered a blood test. A nuchal translucency alone is about 75% accurate, but if it is combined with the blood test the accuracy can be increased up to 85%. The blood test measures the level of two proteins in the woman's blood. These are called 'pregnancy associated plasma protein - A' or 'PAPP-A' and 'free-beta human chorionic gonadotropin' or 'free BHCG'.

Women are given the choice to just have the nuchal translucency, or to have the nuchal translucency as well as the blood test. However, the blood test cannot be performed on its own without the nuchal translucency. The blood test is best done before the nuchal translucency, but it is possible to have it done at the same time. Women carrying twins or more are not usually offered the blood test, because it is not as accurate.

End of website cut

Now if I remember correctly the proteins they're looking for in the blood test can be affected by things like early bleeding during the pregnancy, and as somene has already mentioned, dates (but probably they checked dates during the scan).

Hopefully someone will be able to tell you more soon.

Thanks very much Yurt, think they got the date right as came last week for the test and the baby was too young, today was 12+2 which is the best time to test apparently. Didn't have any bleeding in early pregnancy. The website extract was really helpful, I'm still not sure I really understand (science was never my strong point) but it's becoming a bit less foggy! Thanks again for taking the time.

They haven't been that helpful really Har. I've alwaysn unersootd the nucahl to be more accurate (but have also known people with very good 4000+ nuchal reaults to go n and have a child with DS). Really before getting too concerned the question to ask is what you would do with the information. If nothing much (other than digest it) then your problem is solved (almost). If 'I'm not, i.e. you would act on the information for sure then it's trickier).

I can't help because in pregnancies 1 and 2 I had nuchal in pregancy 3 bloods - (diffferent health authoritires). I never had to wiegh up the results of one against another iyswim (in fact ds1 is severely disabled- just with nothing that could be detected antenatally- adds another spanner to the works!)

You really need to find someone who can explain the results to you withint the swediish system. I hope your brother can help. (giving tests without the knowledge to backup the results with proper advice is a bugbear of mine! Grrrr. ) Hope you get the aswers to your questions that will put your mind at rest.

Try to think of it like this - statistically, out of 420 women with your particular combination of age, nuchal fold measurement and blood tests (so exactly the same test results as you in every way), just one woman will go on to have a baby with DS. That's what your final result means. So you could equally say that, statistically, out of 420 women with your exact combination of factors, the other 419 will go on NOT to have a baby with DS.

So, that's 419 women with the SAME blood test results as you (these blood test results that changed your risk factor), and the same age as you and the same nuchal result, and who will go on to have babies who are absolutely fine. Even though it might seem like a relatively high risk if you were hoping for a higher number, your particular blood test results are still something seen far more with babies without DS than they are with babies with DS.

Obviously someone still be the 1 in 420 - it's not a zero risk - but don't give extra significance to, or worry about, the blood test, just because it changed the risk from something lower, to the 420.

DS meaning Downs syndrome i.e. Trisomy 21, by the way.