Nuchal translucency scan at 12 weeks or triple test at 16 weeks

[Beatie]

My health authority offers the 16 weeks scan but I could get the 12 week scan done privately. What are the benefits of each?

Is it worth paying for the 13 week scan? I have already had an 8 week scan as I have a history of miscarriage so I am perfectly happy to wait until 16 weeks to see the baby but I want to go for whichever option is best for the baby and for us.

Please help.

You know, it really depends on what you will do with the information you get from the test, ie if an increased risk is identified.

If you have the 16 week blood tests and have a high risk identified, your only option then is to have amnio if you want a diagnostic result, which can take up to 3 weeks to come back - that puts you in a position of having to make hard choices at nearly 20 weeks. Or you decide against amnio and have an extra nagging worry for the rest of your pregnancy. (This has just happened to me and we decided against amnio, but I really wish we'd not had the tests at all.) Are you sure they scan you at 16weeks - they did me to check my dates after the blood test results came in, but the dr told me that it was too late really to look at the nuchal thickness.

If you have the nuchal scan and tests, you still have the same decisions to make but at an earlier stage and the results are quicker to come in.

That's probably not much help, but I just wanted to say, don't do what we stupidly did and just have tests because they're offered.

I'm not sure about the triple test as I've never had one, my HA offers the nuchal translucency scan. The NT scan identifies 'soft markers' for Downs Syndrome - Thicker band of fluid behind fetal neck, shortened femur length, and absence of nasal bone. It is important to realise that it is not a definitive test, combined with your age it will give an overall risk. The scan also needs to be done by an experienced operator to ensure accurate measurement.
I have only had NT scans for my pregnancies, it is non-invasive, unlike CVS or amniotomy, but, as I've said you have to be aware that it is not definitive. I'm sure someone else will be able to give you more info on their experience of the triple test. Good luck with your pregnancy.

As mrsflowerpot says it depends what you will do with the information. I have no experience of these but it sounds to me that if you have the earlier scan then you have more time to make decisions if you need to.

I found these FAQs quite helpful
info

I had the 16 week blood test as that is what is offered in my area. It only looks at content of your blood, your age and weight and then gives you a probability of the risk, if it is greater than 1in250 they will offer you further tests (of course amnio and CVS both have risks and can lead to miscarriage). It doesn't look at the baby at all. We did consider the option of paying for a 12 week NT scan (we had a NHS 12 week dating scan anyway), but due to age decided my risks were low anyway. I think you do need to consider carefully what you will do with the results and how at risk you are anyway. It's a difficult decision, good luck with whatever you go for.

I had the triple test, the results came back with a much higher than normal risk of chromosonal abnormalities. I wasn't offered the nuchal scan or a diagnostic scan after the blood test and had an amnio. It isn't pleasant but the only way to get certain results (I think they tested for 170 common abnormalities). If I was to go back again with the information I have now I would insist on having a nuchal scan not the blood test - it is very inaccurate - the amnio would be an absolute last resort. The risk of amnio is actually very, very low if you get someone with enough experience to do it, its just unpleasant. The cost of the nuchal scan would be well worth it.

I had the blood test at 16 wks and came back as high risk. 1 in 150. I went ahead with amnio and do regret it because I would rather have knowledge than anxiety for the rest of my pregnancy.

My region does not offer the nuchal fold test on the NHS and I was unaware at the time that Nuchal Fold could only be done at 12/13 wks. Because of my age (just turned 35) I would have opted to pay for it given the choice. 1 in 150 is only 0.75% so if the NF test had showed a realistically low risk, I don't think I would have opted for amnio.

I had a previous miscarraige years ago but you may decide differently from me.

Hi Beatie - have just looked up in very useful book sitting on my desk:

False positive rate for both tests (Nuchal and Triple) is 5% (i.e 5% of tests giving a high percentage of risk will turn out not to be). Detection rate for triple is 69% and for Nuchal is 80%. So basically if there is an abnormality then the Nuchal is more likely to pick it up. But as others have said they are both screening tests, not diagnostic tests.

Would also echo mrsflowerpot though - it depends what you want the tests for and what you would do with the results.

Highly recommend Fetal Medical Centre 020 7486 0476. The Proff who set this up invented the Nuchal Scan so this centre offers it privately. He also does CVS's and Amnio's and does them all week (Wednesdays privately, rest of the week on NHS)so is very very experienced and has a low miscarriage rate. You have probably seen him on TV filmed at Kings Colege Hospital where he works on the NHS. I had 2 CVS's with him. I chose the CVS even though the Nuchal Scan showed a low chance of any abnormalities as I wanted to be sure. The CVS is done at 10-12 weeks and the results take 48 hours. I wanted to know as early as possible in both pregnancies that everything was okay. Good luck.

chicpea - thanks for that - I am going for my nuchal at 12+1 in two weeks and I am sure my results will be high (as I am 39). Can the amnio be done anytime after that and how do you get referred to the Fetal Medicine Unit (where is it?) or if you go privately, how much is it?

I don't think amnio's done until around 16 weeks and beyond...

Beatie I'd echo what most are saying, you need to think about what the results would mean for you...from what I've read the NT is more acurate, and actually looks at the baby whereas blood tests alone don't but I only have a 20+ week scan in my area so I don't know what they would look at in a 16 week scan. The NT can only be done between the periods of 11+3 and 13+6. We had the NT scan because we wanted to make a decision sooner rather than later if necessary.

Being 39 doesn't guarantee high results. The Fetal Medicine Unit does combined tests these days - NT scan and blood test. I think it cost about £150 for DS2, which was about a year ago.

I don't know about NHS referrals to the Fetal Medicine Unit, but I do agree that they're excellent there, really professional. If I had had a bad NT result on the NHS, I would go for a second NT scan with them, before considering anything invasive and risky.

Beachyhead, I had the NT at age 39 and like you I assumed my risk would be high. Actually it came out at 1:750 which is the average risk at age 29! Shame I don't have the body of a 29 year old though. I had my tets done privately and was told that if required I could have the CVS or amnio on the NHS the next day. Not sure how common that is tho.

My test was a combined blood and NT. Got a video thrown in for £150. Well worth it.

beachyhead, you don't have to be referred to the fetal medicine centre, you just book yourself in. Unless you have some kind of private health insurance that might cover you (mine doesn't). I 100% agree with chicpea, and would definitely go there. I know that if you get the prof to do the test (whichever you go for, CVS or Amnio, I would go for the CVS, the results are back more quicklky....), the miscarriage rate is lower than the national average. For rates, I think they are on the website, which is this: www.fetalmedicine.com/fmc-home.htm
Sorry, can't do a direct link, you'll have to cut and paste!
beatie, for what it's worth, I would go for the 12 week nuchal, and then decide to go for a cvs/amnio depending on the results. As many people have said, it depends what you would do with the info, as to whether you really want it or not. I have had the nucahl on the NHS, but always told myself I would go to the fetal medicine centre for a 2nd opinion if I felt the results were a bit iffy, or for any more invasive diagnostic tests. I don't know if you are London based though.....
Hope that helps, and good luck to everyone with difficult decisions to make.

The nuchal translucency test won't necessarily indicate a high risk on age alone - that would rather negate the point of having it! I was 40 and it wasn't high - can't remember exact figure, but the risk of m/c from cvs or amnio was quite a lot higher. You could proceed to cvs immediately after the test if you were still concerned, but no point having cvs (IMO) if you wouldn't consider a termination. I would definitely go for the nuchal fold test rather than a blood test. More accurate.

I was told NOT to have the nuchal fold test and the blood test as they can give conflicting results. Was advised by my GP that the nuchal fold test was slightly more accourate so paid to have that done. Did not have the blood test.

Slight confusion here I think. The Nuchal Fold test includes a blood test the results of which are combined with the scan results to give you the risk factor. Janeybops I think you were probably told (as I was) not to have the triple blood test(the one that is routinely offered) as well as this will give a different percentage risk than the NT and therefore cause confusion.The results of the NT combimed with the blood test are more accurate than the Triple test.

Just remembered that not all places offer the combined test, though the clinic I went to and The fetal Medical Center do. The combined test is more accurate than the scan alone. The test will apparently become more accurate again when they include the detection or otherwise of the presence of the nasal bone. Although the scan can tell if the bone is present they have not yet worked out the mathematical implications and therefore although my scan detectd the bone this factor did not figure in the result.

Thanks everyone - I have my nuchal scan in two weeks and dh and I are already discussing it. A friend who had her last baby last year at 39 had odds of 1:35 before the scan and 1:250 after, and everything was fine. I think we just need to wait for the figures, but its great to have a recommendation of a good place (if that is possible) for any follow up procedure.....

The nuchal fold test does not routinely/invariably include a blood test. At Kings in London which is a world leader in scanning, they do not offer a blood test as it is considered to be less accurate than the NT (nuchal translucency) test. And they do look for the nose bone and femur length as markers, but don't include those in the statistical results yet.

The nuchal fold test does not routinely/invariably include a blood test. At Kings in London which is a world leader in scanning, they do not offer a blood test as it is considered to be less accurate than the NT (nuchal translucency) test. And they do look for the nose bone and femur length as markers, but don't include those in the statistical results yet.

You can have a NT test alone or the NT test combined with a blood test. The latter is definately more accurate. I doubt that they would do a blood test if the combined results were less accurate than the NT test alone. I had the combined test (not to be confused with the triple test) this is exactly the same as the one offered by the Fetal medical centre. Can't speak for Kings but I had my test reasonably recently and was told the combined one was the more accurate