Down Syndrome

I will just chirp in here again. There are actually guidelines for NT testing. They are quite specific about when u/s is done and when blood test is drawn. This isn't something that differs state by state it is a standard thing. What different practices do will depend on the doctor in that practice and the experiences that have led them to practice as they do. That would be something to discuss with an individual practitioner.


When the blood test is incorporated into the u/s result the number of cases that "slip" through have been decreased to about 5-10%. Without this the rate is around 15%.

It is quite true that the doctor is primarily concerned with the NT measurement - what is an okay measurement is dependent on the gestation. He/she is also concerned about the nasal bone and other soft markers. Fetal Medicine units use very wizz bang equipment and the obs are highly skilled at doing these tests. Babies with chromosomal challenges (even down's syndrome) can and some do have a normal nuchal fold measurement for their gestation. However, it is usually the other soft markers and the bloods that highlight an issue in these cases. It has been shown that the bloods can throw that test when the levels of HcG are high for gestation and the PappA is low for gestation. Both high hcg and low Papp A are indicators of chromosomal irregularities in the baby but are not definite diagnosis of this.

Remembering this is a screening test...

I have personally cared for women who have normal nuchal fold and the bloods being out of whack is what alerted to the possibility of a chromosomal irregularity. I am concerned that people don't think that the blood test is of no consequence because it can be very helpful.

It is true to say that the reliance is placed primarily on the u/s result providing it is done by a highly skilled and experienced operator. But I don't believe it is true to say that it is not helpful at all in this screening process. I do believe it is the cause of the high number of "false positive" screens and I have also personally witnessed this also. So, that in itself is an issue.

The combination of bloods and u/s has only been available for approximately 4-5 years and is a relatively new component of this test.

Again, I really feel strongly that people are not frightened off nor afraid for their own experiences in reading this post.

As in all things health and pregnancy related it is important to seek information from a well documented source. :hug:

Yep flowerchild I totally agree. Max had a normal nuchal fold reading, it was the blood levels that indicated the problem.

Can I just say, Debbie Lee you definately were not insensitive in any way, everyone holds an opinion on this testing and what you do and others do is a personal choice. You have the right to your own say and should not feel bad for feeling the way you do or writing it down. MWAH

My only advice to anyone, is don't Not have the scan because you wouldn't terminate if there was a problem, you really never know how you will feel until you are in the situation. Believe me, I never in my wildest dreams thought I would be in the situation of a life or death decision for my unborn baby, but sometimes it is the choice of least harm and these scans provide you with valuable information.

I am just wondering now whether the OP has had her NF scan or not. lol we seem to have gone completely off topic. lol

Thankyou Michelle and Deb for your kind words, amazingly it was fellow nurses that held this opinion. You would think they would know better!

Thanks for sharing your's and Max's story Clare. :hugs: I know just how long and hard this journey has been for you. Some nurses can find it hard to walk in someone elses shoes - I understand.

I am glad you shared your experience s - I was very alarmed that folk would feel that they may not need the bloods done. Also, as you pointed out it's important to know that the NFT can alert to other chromosomal conditions not just Trisomy 21.
It is all in the hands of the operator. I urge women to seek out the stats of the unit you plan to have your NFT done at so you can feel confident in the outcome... :hug:

My doctor said to go in around 12 weeks for both. The place where they do the scans said that I should have my bloodwork done a few days before the scan. I'm going in for the scan at 12 weeks and 4 days. Originally I was going to just do my blood test at the same time.

Do people usually get the bloodwork done before the scan?

I don't see my doctor until week 13.

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IIt is true to say that the reliance is placed primarily on the u/s result providing it is done by a highly skilled and experienced operator. But I don't believe it is true to say that it is not helpful at all in this screening process. I do believe it is the cause of the high number of "false positive" screens and I have also personally witnessed this also. So, that in itself is an issue.

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Just thought I'd add this in case anybody gets confused ... false positives are guaranteed at being close to a certain rate for screening tests like this. For example, they will pick a ~5% false positive rate for a ~90% detection rate. Depending on the exact method used, thats about the rates you get for NF+bloods. They could reduce the false positive to say 2% but the detection rate will drop to say 65% (last figure a guess just to illustrate what I'm saying). A 5% false positive means 5% of *all* women screened will get a false positive - so 1 in 20 will get a positive screening result even though most of these will be fine. (It doesn't mean 95% or even 5% of positive screening results will have a positive CVS/amnio result - its down around 1% somewhere).

Lilbean i had my BT done a week before my scan i think you get the results quicker if you have the BT done a few days before.

OK, I had a NT scan, but no blood test. My doctor never mentioned or suggested it, and I had not heard of it before I read about it on BB.

How much of a difference can it make to the results if you just have the scan results? should I be asking to have both (if theres a) next time?

Rayray I only thought the results worked if you had the BT done as well. The NF could be okay but the BT can change the results.
When did you have your NT scan ? Did they say what your results where ?

The optimum time recommended for the blood test is 10- 10 1/2 weeks follwed by the scan at 12 weeks. The most accurate results are when the two are done in combination.

Each can be done individually but as I said the most accurate is when they are both done and at the correct time.

These tests are screening only and not diagnostic.

Thanks for all the answers. I had the ultrasound done to receive the thickness of the piece of skin. under the risk stage which is great. did a full check up of bubba and its 50mm and with a heart beat of 163. the only concern I have is that they found a subchorionic haemorrgage measuring 42 x 12 x 39mm almost as big as bubba. I haven't seen my ob yet, i have an appointment on the 12th jan sure i try to get in eariler of wait, the doctor who did the testing didn't seem too concerned about it, should I be, i have been trying to find out some information on it and the only thing i can find is that it can cause bleeding???? how worried should I be about this

Ray Ray,
There are still places that only do the u/s you certainly are not alone. Now there are much fewer places that do NTS without the blood test. I would definitely ask for it next time if you decide to have the NTS.

Yes, I think if I have the NT scan next time I will ask for both.

I just had a normal 12 week u/s with Milo and they measured the NT while I was there, and from memory it was 1.2?

Hi Ladies
wow this was very informative. I was wandering what the link to the BTs was with the scan so thank you.
I am having my BTs done 10 days prior to my 12 week scan where they will be doing the Neuchal Translucency fold Scan. If I end up being in a high risk cat of having a baby with Downs, I dont think I will do a amniocentesis. But if there is a chance to know early on that I might have a baby with DS then I'd like to know. My eldest brother was born with DS and my mum was only 27 when she had him. All the doctors I have spoken to though, say that my risk is no greater than anyone elses.
Thanks again for all the info.

I just want to thank everyone for the feed back, went and say my ob yesterday and everything is ok the subchorionic haemorrgage they found was only a blood blister that had burst, it had just burst on the day they did the ultrasound so which made it look worse becuse it had spread, everything is ok and its now smaller that what it was on the 28th december. still had no bleeding from it but my ob says if i do there is nothing to worry about. all is okay and bubba is moving around like there is no tomorrow having lots of fun doing its exercise classes.

THANKS HEAPS

I read earlier in this thread that there is a common belief that a family history of Down Syndrome increases your own risk. this is only very marginally true.
There are 3 types of DS - Trisomy 21 (95%), Translocation (4%) and Mosaic (1%). of these, the only one which is thought to be hereditary is Transolcation, which effects 4% of all people with DS.

for example, although i have a brother with DS, as he has Trisomy 21 DS, i am at not at any increased risk of conceiving a child with DS than the rest of the general population.

This is a bit off topic from the original post, but just thought i'd put it out there to alleviate concerns of those with relatives who have DS, and might be unnecessarily worried ...