Taking age in to account with Triple Blood Test and 'Risk'

[PutThatInYourPipeandSmokeIt]

With DD 15 months ago (I was 36), my risk came back as 1:10,000

This time, it was 1:569 (I am 37) but still described as 'low'.

Can anyone tell me why the numbers are SO different - is it my age??

I know nothing about the test but I post on SANDS forum and there are a lot of ladies who have been told that their risk result will automatically come back high because of their previous loss. Apparently much of the risk is calculated before the blood sample is even checked so I would assume that age would make a difference.

Hmm don't know. I'm 35 (coming up for 36) and my risk this time with bloods was 1:1900 so I think your risk ratio last time was pretty amazing. I'm anxious as this is my no3 and planned last one - scan on Tuesday.....

They check 3 different hormone levels in the blood,these are then compared to the statistics for women at your age, at the same stage of pregnancy with the same hormone levels. For babies with downs two hormones are usually raised and one lower. I was told by my mw that the triple test isn't as accurate as the nuchal scan. I'm 31 and my triple test came back as 1 in 30, had the amnio and was given the all clear. I was told that sometimes these hormone levels are different for reason they don't know, such as having a big placenta.

I think the more amazing thing is that 1:10,000 risk from the triple bloods -- I never heard of anyone getting such low numbers, before. The 1:569 is much more typical for a mother in her 30s (still quite good for age 37).

Anything better than 1:250 is classified as "low". So you could be 1:10,000 or 1:251. The point of splitting everyone into "low" risk and "high" risk is that the high risk women are automatically offered amnio (although they don't have to take it of course).

I surprised that you could get 1:10,000 at 36 by the way. I was told that I was as low as I could get for my age when I was 34 and that was 1:5,000 (or thereabouts).

PS at 36 your risk using your age alone is 1:260 (can't remember exactly, but it's definitely in that ball park), so 1:569 is really good.

oh thanks ladies, that's most reassuring. Very curious about my previous result then - perhaps it was a typo. The nuchal was at 5.8 at 20 weeks and I understand that the upper limit is 6, so I was starting to put 2 and 2 together..... and get 7!

OK, just checked online - 6mm is still normal at 20 weeks. So as long as you're not over 6mm, your risk won't increase. Your blood results must have been really good to drop your risk to 1:569.
The upper limit is 2mm for 12 weeks, and that's what I've had in both my pregnancies, but I've always had low risk too. The upper limit of "normal" is fine, as long as it's normal.

Thank you that's great

My results came back at 1:225, I'm 36 and the Dr advised me she recomended an amnio, however, when she discussed it with the Obstetrician, he felt that as the Nuchal test had come back as 1:750, the combined results meant I was lower rather than higher risk, and so he is sending me for a"super-scan" (no I don't know either) on Thursday, although all that said, I live in France, and things are slightly different, so we'll see....

OK, sorry to gatecrash but now you are all scaring me, I'm 37 and having had 2 previous m/c's plumped for a private combined Nuchal and bloods test. However my combined test for both Downs and Edwards is 1:50,000 are we saying that this isn't possible? I've just been to check the documentation and that is definitly what it says?

jenpet - some people have an ultrasound that looks more more closely for characteristic signs of Downs - things like the presence of a nasal bone and (I think) limb length. That's exactly what I would have gone for if I'd had a high-risk result, as it doesn't have the (slight) miscarriage risk of an amnio. It will tell you if the baby is likely to have Downs, but it doesn't give a definite answer like amnio. At 1:225 you're only just in the high risk category, which is probably why your OB thinks that you're a good candidate.

Hm. This is a tricky one. With DD1 (me aged 35) my risk was 1:2010 and with DD2 (aged 37) my risk went down to 1:3600! Have to say that DD2 was in a different hospital where they did nuchal plus blood screen. DD1 was nuchal alone.

I think a lot of the number crunching does more harm than good, though, TBH. The odds of having a baby with Downs Syndrome are still really low at 1:250, even though the mother is in the high risk bracket. You wouldn't put money on a horse at 250 to 1, would you? I suppose theoretically that if your odds were 1:10,000 someone is still going to be the one.

There was a really good explanation on another thread recently, which I'll try and find a link to.

Thank you MrsTittlemouse the Dr hadn't explained what the ultrasound involved half as well as you just did (I was rather hoping it would be a fab 3d one!)
But that makes sense now, when I had DS in the UK, I only had the nuchal test, as it came back low-risk they never did the triple test, and I keep telling myself if I hadn't had it this time I wouldn't be worrying now either....agree too much number crunching does more harm than good too...

my doctor called me today, and my ratio is 1:225, even i dont believe in this im still scrared, im 28 years old, and i dont have any in my family with down syndrome, i have an appointment with the genetic consoling next week,will see what he is saying. i think they take money from the insurance and make us do hundreds blood test. at the beginning they said i had thyroid, i did the analyze one more time, and the next week my thyroid was normal, how come???? how it came normal without any medicine and within a week??????/ these are bullshits they are only worrying us