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Hi Girls,
Hope this finds you all well. Just wanted to ask with the NT 12- 13 week scan, did you have the blood test the same day or the weeks before. My Doctor was saying something about having to have the blood test at 10 weeks and then the scan at 12 - 13 weeks?
Thanks
Kristy
I think you can have the BT done from 10weeks onwards. I had my done a week before my scan so i was just over 11weeks pg.
I think they like them done before the scan as it can take a while to get the results i was told at my scan yesterday it would take 5 days to get the results.
My OB sent me for mine at 10wks and I had the scan at 12wks. What OB are you with in Perth??
I am with Anna Holmes in Perth but as I am in the country I will proably do shared care with our local GP.
Can I ask a dumb question....
I'm booked in for my NT scan at 13 weeks but there was no mention of a blood test either at 10 weeks or on the u/s day? The referral form has got "Maternal Chemistry for Downs" written on it as well as the request for the U/S is that the BT?
Emma,
Could be an age thing?
The risk is really low in your 20s and increases with age. By the time you are over 35 it is much higher so they are more likely to test.
So if you were at the younger end of the scale - they might not test. Would that explain it?
Wow... I wasn't even told when to have the BT. I am booked in for my NT scan on 4 Aug, and when I booked in, the only thing they told me is not to have the BT done before the scan, on the day of the scan. I thought I would have it done on the same day, but after the scan. I will ask more for more info at my appt on Monday.
Lisa
i thought the same thing about the age risk thing, cos i'm only 26, but my ob said it's not about age, it's about whether you want to know or not, cos it happens at any age (of course the risk is lower in lower age still)..
anyway i heard that the best timing is 10wks for the BT and 12wks for the US/NTT..
but i went for my US/NTT at just before 13wks with no BT (i was slack organising it), and the doctor said i could still go for my BT even at 13 wks..
and that the US/NTT on its own picks up 75%; together with the BT it picks up 95% (or something like that), that's why they usually send you to both, for greater accuracy/sensitivity..
Kar the chemistry for downs is blood work.
Now NT ultrasound is done in conjuction with bloods. This gives a more accurate picture of a baby's development. I know things can be a little different when done through a public hospital. It takes time for the results to come back to the mother and I believe not all hospitals do the blood work in conjunction with the u/s.
If you are having nt u/s with a private ob you will sometimes be sent to a foetal medicine specialist - usually an ultrasonographer will do the initial scanning and measurements and then the foetal med. ob will come in and check it out. You will then be given your risk assessment on the spot it will be given as a 1:??? result. You will be told what your risk factor is just based on age 1:300 for example and then be given your result when the nuchal fold is measured combined with the risk factors from the blood work.
Most specialist ob's prefer to do the nuchal fold at around 12.5 weeks - this gives the best view for measurement of the nuchal fold. After about 13.5 weeks the nuchal fold begins to disappear as the baby grows so it is more difficult to measure. Most specialist ob's will require that you have the blood work done a few days prior to the u/s so they have the results to combine with the measurements.
The combination of blood work and u/s measurement of the nuchal fold and u/s examination of the baby for other soft markers is thought to give the accuracy of nt u/s up around 85% - 90%. Without blood work the accuracy is decreased. This is because some babies with chromosomal defects do have a normal nuchal fold measurement. The extra info that the blood work gives gives a more rounded picture.
NT U/s is not a definite diagnosis and when there are any red flags you will be given the option of amniocentesis or cvs. I believe it's really important to ask your ob what the accuracy rate of the practitioner you go to see has. For instance I worked with a foetal med. ob and his nt u/s accuracy was 100 per cent. Meaning that he had never had a case slip through.
Some families are more comfortable with waiting and hoping that there little one is fine and embrace whatever comes along. For other families they need to know with reasonable certainty that their little ones are 'okay'. Niether is right or wrong it is a very personal and emotional choice. It is erroneously believed that chromosomal abnormalities of which Down's Syndrome is the most common is confined to 'older' women. This is patently incorrect. Yes, the risk factors increase with age but it is now believed that there are links with nutritional deficiencies and down's syndrome as well (that's a whole other story!). I have a friend who had her son who was born with Down's Syndrome (Trisomy 21) when she was 27. She went on to have 3 other children her last at 40. Her other children were not afflicted with Trisomy 21. She has done mountains of research and there appears to be a very strong link with low levels of folate and zinc and higher incidences of Trisomy 21....
Anyway if it is important for a family to feel reasonably secure that there baby is not afflicted with a chromosomal abnormality I think NT U/s is a very good option. However it is my opinion that it is important to have it done with a foetal med ob.
Flowerchild - thank you - that helps heaps.
And thanks to everyone else for their info too.
Armed with all that info I decided to ring my Fertility Specialist and ask about why the BT is at 13 weeks along with the U/S and was told very very firmly that their evidence is that it the most accurate at exactly 13 weeks and no more. So they weren't gonna budge on the date. (Bummer!)
I find it fascinating that even amongst the few of us who have posted there is so much difference in opinion in our care givers! All I can say is half your luck if you are having tests done at 10 wks or 12 wks. I still have 3 w and 1 day to wait and time is moving at glacial speed for me at the moment!
Good luck everyone.
Kar, the specialist I worked with (and literature supports the nuchal fold meausurement taking place late in the 12th week/early in the 13th) was standard 12.5wks for nuchal fold u/s- this is simply because it is more accurate done later than earlier but we didn't want it too late in case growth made it difficult to measure. Often women would come and be just too early to give an accurate picture and need to return again. Dates can throw things a bit. Your specialist is only 2 days ahead of mine. I am sure you would find if you were 12.5 weeks on a Thursday and there were no appts left until the following Thursday he would do it. Do you know what I mean??? If a woman is close to 13 weeks give or take a day or so...
It sounds like your specialist will not give you the full results on the day because the bloods are being taken on the same day. This will mean that she/he will measure the fold and u/s your baby and give you a risk factor. A few days later you will be contacted with the adjusted risk factor when the blood results become available. Some units do it this way - I am not sure why as there isn't really a medical reason why but doing it this way isn't unusual.
I truly understand how time drags until that ultrasound. I empathise with you ((hugs)). Rest assured though you will get a nice accurate 'picture' of how things are going in wombville! I agree there is often much discrepency between care providers - though most agree on the time frames for nuchal folds now. In the early days it was earlier between 11 and 13 weeks. I think as time has progressed and more experience and knowledge gained we have more information on accuracy.