Risk of Downs Syndrome

[Heaven]

Ok so I have read 2 things but I can't see how they go together, can someone please explain??

1- The majority of DS babies are born to younger women.
2- You are at a higher risk of having a DS baby if you are older.

What the?

[Muppity]

Younger women are less likely to have the tests.

[Nicambhar]

My dr explained this one to me as I was confused at how this can be. Younger woman seem to have more babies than older woman so therefore more chances to have a DS bubs. Make sense..

[satya]

Basically most women having babies are in their twenties and early thirties therefore they have most of the babies with downs syndrome even though their risk factors are lower. They are also more likely (particularly those in their 20's) not to bother with the testing as they often don't realise they are still at risk.

Older mothers (over 35) are more at risk due to older eggs but they are also more likely to have the scans and amnios as they know they are at a higher risk. New research shows that women over 35 who have partners under 25 (like me) have half the Downs risk of those over 35 who have similar aged partners, even though most doctors have never heard of this research and don't take it into account.

The other interesting thing is that most women who get a high combined risk NT result will not have a DS baby, yet having a good result does not mean you wont have a baby without DS (although it seems to me a lot of people seem to think it does).

Regardless of all the testing available, even if you've had an amnio or CVS which shows no abnormalities you can still get a surprise on the birth day and have a DS bub.

It's all very complicated.

[Smoke Jaguar]

If this is of concern, I would definitely recommend reading Dr Sarah Buckley's book Gentle Birth, Gentle Mothering, no matter what parenting orientation you take.
It has a couple of really good discussions about prenatal diagnostic testing, with much reference to research about not only incidence of DS and other congenital 'abnormalities', but also quality of life studies of the mothers of these kids. It's an awesome read that serves to really get you at peace with whatever's going on If your local library doesn't have it, you can request it, and your local ABA group might even have it in their library.

[Mother Goose]

My Ob also told me the high incidence of babies being born with down's to younger mothers is because they decline testing with the belief that they are not "high risk" and so it is not detected and the pregnancy is not terminated if a positive result returns.

[Heaven]

Thanks girls!! That makes sense now. I couldn't work it out, lol.

I was just reading some things about having a 12 wk scan or not and came across that. I can't decide whether to have one or not!!! ahh...
When I saw my Dr to confirm the pregnancy etc she said she doesn't recommend having it b/c I'm low risk and the results are often unreliable and you could end up going through further uneccesary testing if you are high risk and the baby turns out to be fine! Lots of extra stress and chance of miscarriage from the extra tests. That all makes sense and logically is a great idea.
BUT now I keep thinking what if something was wrong and there was no heartbeat or something?? (maybe I've been watching too much neighbours, lol!). I'm planning to tell ppl after 12 wks that I'm pregnant but I won't actually know everything is going to plan then if I don't have the 12 wk scan will I?? I should just try and be positive and assume everything will be fine which it most likely is but I can't make up my mind if I want the scan or not!!
Any advice?

[Lulu]

With my third I declined most of the tests - esp the DS one. Why? because no matter what the result I knew I wouldn't terminate, especially so late. When Dp and I talked about it we both agreed we couldn't abort just 'cos there may be DS.
I don't think Downs is a terrible enough reason to end a pregnancy, that's just me.

[Heaven]

I don't think I would terminate either. Though I would like to know, do they test for DS at the 20wk scan too?
I more just want to know everything is going ok. Maybe I could just have a u/s to see the heartbeat but not have any screening????
But then I think, ppl had babies for thousands of yrs without having scans and I just want to see the baby and that everything's ok, it's not something to help the baby, I should just leave my body alone to do what it's supposed to be doing!! lol.

[Smoke Jaguar]

I'll just reiterate about Dr Sarah Buckley's book. I would consider it important and relevant prenatal reading, personally, and have a girlfriend who read it and felt the same (she currently pregnant with her first). It'll get your mind back on track
ETA:
When I was pregnant with Osc, I assumed all this 'routine' prenatal testing was a rite of passage, so I did it. My conscience was first alerted, however, to the pervasiveness of this mistaken belief, when I went for the blood test. The nurse at the pathology place sat me in the chair and I told her that I hated giving blood samples (despite a few years of blood donation!), and she asked if I'd been sent to her by the doctor. I said no, and that I was having it done to test for 'abnormalities' (I now use that word, in relation to babies, with trepidation) and she remarked "who's told you what to have you scared enough to have the test?". We had a chat about it, briefly, and we agreed that I realised I was in a very low risk group, to begin with, and second, that I wasn't as sure as I thought I was that I WOULD terminate if I found out. That nurse really started me on the road to thinking!
Also, since I posted the first time in your thread, I had an interesting encounter with someone. I was getting to know someone who is involved in my fire brigade, who I hadn't thought to talk to on a friendly, personal level before. He was talking about his kids, I was talking about Oscar and he revealed, in the most normal manner, that his middle child has DS. I was saying how great it was that his older and younger brother and sister could have a brother with DS because of what they have to offer, and how it was so good for that child to have 'normal' siblings, in order to facilitate integration into the mainstream world. Anyway, in this same conversation, he said that his wife refused to have diagnostic testing, even after halfway through the pregnancy when she just knew something was different from 'normal'. I was so impressed with this and it reminded me of your post and of the good Dr Buckley! The upshot here is manifold: two 'normal' kids either side, the family is challenged now and again but so happy and balanced, his wife was able to enjoy the pregnancy and knows now she can adapt to anything, and DS kids are a real blessing.
The point is, it works out quite well when you don't have diagnostic testing, whether you end up having a 'normal' child or a DS child.
Enjoy being UTD!!

[Heaven]

Thanks mayaness, I am going to try and track down that book. And thanks for the personal perspective!!

I'm also just worried about what if I had a missed miscarriage or something and I tell everyone that I'm preg at 12 wks but don't know!! I have no reason to believe this is the case, lol, just being paranoid. And I know it's not that common. I'm just being a worry wart.

[~Belinda~]

I have heard the risk is greater when the woman is older. I had the nuchal translucency test at 13 weeks and my risk was 1:7500...but my girlfriend had her test and it was 1:45 so she opted for the amnio test after that. I always wondered, what happens if it does come back with DS? Can you terminate at 13 weeks anyway? I didn't even think of that when I was pregnant but I wonder now!

[Mumof2Girls]

Regardless of all the testing available, even if you've had an amnio or CVS which shows no abnormalities you can still get a surprise on the birth day and have a DS bub.

How is that possible? The amnio and CVS are chromosomal testing and they'd notice if the extra chromosomes were in the result.

[Lulu]

You can hear the heartbeat at your Dr appointments, you can even get a monitor yourself babe.

I do know what you mean, I did have one u/s with DD2. I needed to see it after my missed m/c.

However, you can't help worrying no matter what - but try! xoxoxoxoxoxo

ETA! Bindy thats exactly my point, what would happen if the test came back pos for DS. Well nothing as far as I'm concerned so there was no point to the test.

[satya]

Regardless of all the testing available, even if you've had an amnio or CVS which shows no abnormalities you can still get a surprise on the birth day and have a DS bub.

How is that possible? The amnio and CVS are chromosomal testing and they'd notice if the extra chromosomes were in the result.

If you get a positive result (meaning a baby has DS or one of the many other trisomies) that they test for then this is 100% that the baby has it. If on the other hand you get a "no abnormality detected" it means just that - no abnormality detected - it does not mean 100% that your baby will not have a trisomy - it means that it is extremely unlikely that it will have them that's why they use "no abnormality detected" - to cover themselves just in case something in the test did not work. Extremely rare to have that happen, but it can happen.

[satya]

SaraJane - in answer to your question about if they can detect DS at the 20 week scan. Again, it's not a simple answer. At that time the nuchal measurement will most likely have decreased and that's one of the markers for DS. If other markers are present at that time (like heart defects & nasal bone abnormalities) then they might recommend an amnio. Of course by that time it would be too late to abort, that's why the earlier testing is recommended. Some DS babies however look completely normal throughout all the scans and the parents have no idea until they are born.

[HotI]

If you get a positive result (meaning a baby has DS or one of the many other trisomies) that they test for then this is 100% that the baby has it. If on the other hand you get a "no abnormality detected" it means just that - no abnormality detected - it does not mean 100% that your baby will not have a trisomy - it means that it is extremely unlikely that it will have them that's why they use "no abnormality detected" - to cover themselves just in case something in the test did not work. Extremely rare to have that happen, but it can happen.

The possibility of this occuring is minute. But here is an explanation of how it could theoretically happen.

CVS take a sample of cells from the chorionic villus (the finger like projections) from the placenta and examines a number of the cells to see the chromosomes. The original cell (that creates the baby) splits and splits again and again to produce the placenta and baby.

For a baby to have Down syndrome, and CVS to show no cells containing three copies of chromosome 21 (which causes DS), a mutation must have occurred only in the cells that went to produce the baby (and not in the placenta).

If this occurred, it would also be possible for only some of the cells in the baby to have three #21s, and depending on their location would influence the 'level' of Down syndrome.

Amnio takes a sample of fluid surrounding the baby which contains cells that have been released from the baby. These cells are closer (in age and arrangement) to those in the baby that cells from CVS, and thus are a more accurate representation of the baby.

If the baby is formed by some cells that have two #21s, and some cells that have three #21s, and the amnio sample only contained released cells with two #21s, the result would come back as "normal". For the sample to contain only cells with two #21s, it is more likely that there is a higher ratio of these cells to those with 3 #21s in the baby.

The chance of a CVS or amnio reporting a false 'normal' result is extremely tiny, but i guess the possibility is still there.

k

[paradise lost]

I know a woman who had CVS and had a terribly damaged placenta with several different trisomies. She declined a termination because one of the trisomies always results in foetal death anyway and she felt she'd rather let the baby pick its time to go, as it were, but now she has a 3 year old, healthy, son. The placenta had abnormalities which the baby did not. No, i don't know how this works, presumably something to do with RNA versus DNA (Ryn where are you?!) but still a scary (for me) story. They cannot give absolutes in the tests, they can only give a most-accurate guess. Nothing is certain.

I don't know the Aus law but the upper limit for abortion in the UK is 24 weeks, though in cases where the baby will not survive anyway (fatal abnormalities like anencephaly and certain heart conditions) they will deliver it early after that time and not make any attempt to help it live.

I personally did not have the tests because i knew i would not terminate no matter what, and i do not believe intellectual knowledge can prepare one for the arrival of ANY baby, healthy or otherwise. I read the chapters in my baby books on DS and premmie babies along with all the other chapters and worked on the basis that it COULD happen to me but it probably wouldn't. Really DS doesn't mean anything certain, there are different kinds of DS, with different severities of effect. Some DS people are very handicapped, some not at all. To me it's like a test to see if they will be blonde or tall or optimistic people - it means something yes, but by no means everything about them will be about DS, if they di have it. It's a very personal decision. Having lost 2 babies i could never risk miscarriage to diagnose something that required no "action" anyway.

Bx