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triple blood test and amniocentisis

(8 Posts)
Linnet Fri 08-Aug-03 00:52:34

Ok, so I'm not pregnant yet but we are actively trying this month.

We didn't get the amniocentisis test done last time(6 years ago now) I was only 20 at the time and thought that everything would be fine and it was. However now that I am older and know more, due to reading websites etc I'm worrying and I'm not even pregnant yet. My questions are below.

Q1)The triple blood test: what exactly does this test for and when is it done? Does this tell you if you have a X in Y chance of having a downs baby? does everyone get one regardless or do you have to ask for it to be done?

I only remember getting blood taken once last time to test for rhesus factor and don't remember any more, there may have been other blood tests but I don't remember them if there was.

Q2)Do you get an amniocentisis depending on the result of your triple blood test or is this done because you are high risk/want to have one?

Q3) is CVS a better choice than amniocentisis or not? Is this a relatively new test? as I've never heard of it before seeing it mentioned here on mumsnet.

After discussing it at length with Dh we have both agreed that we would want to know and will have an amniocentisis test done at the time.

Can anyone answer these questions or give me a link to some information that talks in plain english where I can read up on it. Is there somewhere I can look at that will give me the risks of downs in relation to age?

thanks for any answers,links,help,advice. We want to get all this straight in our minds before getting pregnant so we know what we'll do in any situation that occurs.

Ghosty Fri 08-Aug-03 04:45:20

Dear Linnet ....
There is a link somewhere on mumsnet to do with DS risks according to age ... I will try to find it .... but I am not good at searching on this site so don't hold your breath!!!!
If you are only 26 your risk of DS according to your age and no other tests will be very low ... I am 33 and my age related risk is 1:357 (recently had my nuchal fold test) which in itself is not seen as high risk ... after the test my risk went down to 1:2965 .... so for me there is absolutely no need for an amnio.

I have a friend who is 41 and just had her 2nd baby ... she decided to bypass all tests and go straight for an amnio as her age related risk was something like 1:100 (and anything less than 1:250 is seen as high risk) ... she didn't see the point in having all the other tests as she was older.

When I lived in the UK I never really heard many good things about amnio tests as there is a risk of miscarriage and I think I heard some horror story which said that for every DS baby that was diagnosed with amnio ... 3 healthy pregnancies were lost due to the test .... I don't think that I could go through with that unless I was given a really really high risk.

However here in NZ most of the other mums that I have made friends with have had the Amniocentesis test as for some reason most of the mums I know are older than me and only started their families late on in their 30s. Every woman over 35 in NZ is offered amnio if they want it. Kiwis do not seem to have heard the same horror stories about miscarriage as I had in the UK, and no one seems bothered about having the test.
My friend that I mentioned in the other thread who had CVS, only opted for that as it could be done earlier than Amnio (CVS can be done as early as 11 weeks whereas with amnio you have to wait until at least 15 I think) ... After her 12 week scan she was given a 1:140 chance of DS and she couldn't bear the thought of waiting until later for a definite result so she had the CVS immediately.
Apparently CVS test has no higher risk of miscarriage than amnio.... I think there are other complications attached to CVS ... but I don't know enough about it .... maybe one of the midwives (mears et al) might explain that one ...

One of the things a friend of mine said to me when I was having the same questions as you was "Think about what do you want to do with the information?"
Basically .... if you are one of those people who would not mind if you had a DS baby and would love it whatever then what is the point in having an invasive test that could potentially miscarry your baby? Therefore don't have the test ...
If you are one of those people who are not sure and don't think you could continue a pregnancy if your baby had DS then take the risk and have the test ... and then do what you have to do ...
It sounded a bit harsh to me when she said it ... she had an amnio because she knew that if her baby had DS she would terminate.
Personally I don't think I could get to 18 weeks and then terminate if I found out my baby was a DS baby so I don't know if I would have had the amnio test anyway at all had my risk been high .... but it is all personal isn't it? .... and to be honest I don't what my husband would have wanted had we had a high risk ... luckily we haven't needed to get into a deep and meaningful about it.

Finally ... (phew, I hear you say ... get on with it Ghosty!) ... just wanted to say, it is so easy to get caught up in the risks/test/what ifs that you can lose sight of what is important ... a baby ... You, at 26 are still very young and I don't think you need to worry too much about all of that ... just get trying for that baby and enjoy (the trying that is )!!!

Sorry for the long and rambling post .... just a subject that interests me ....

zebra Fri 08-Aug-03 06:39:57

Good previous Mumsnet thread on Amnio . Ghosty says good things except that

1)I have always heard that CVS is more risky (CVS =maybe 1 or 2/100 result in miscarriage, amnio more like 1 or 2/400 risk),

2) CVS *can* be quite painful(2 people who had the procedure told me that), whereas amnio is hardly more than a pinprick.

3) CVS tends to cause limb deformaties if done before 11 weeks (amnio also can cause limb deformaties if done before 15 weeks).

Linnet, I think you would find the best info in one of the thorough pregnancy books, "What to Expect..." series comes to mind. Otherwise:

Q1) Triple test usually offered to everyone; gives you the statistical "odds" of having a baby with chromosone defect. But it doesn't detect more than 20% of chromosone defect babies.

Q2) You can insist on amnio or CVS regardless of your test results, but doctors will advise against it unless your defect risk appears greater than the chances of the amnio/CVS causing miscarriage. I imagine at age 26-27, your defect risk won't be high unless you get a bad nuchal fold test result.

Q3) Amnio is "better" because it is lower risk, less unpleasant (but may not get final results until 18-20 weeks). CVS is "better" because you can get results earlier (12-13 weeks). NO point in taking either test unless you know you'd probably terminate for the probable condition. Both amnio & CVS carry very tiny additional risks to mother & child (may not result in miscarriage, but other physical harm possible; do not enter lightly).

Some centres (probably The Harris Birthright Trust in London) do combined blood & ultrasound tests. Maybe? costs around £200, but should pick up something like 92% of all chromosone defect babies. Best detection rates possible using non-invasive/low risk tests.


Table 2
All Chromosome Abnormalities Risks for pregnancies that don't miscarry before 2nd Trimester
Maternal Age (Years)at birth
20 1/526
25 1/476
30 1/400
35 1/204
40 1/73
45 1/23

tabitha Fri 08-Aug-03 16:03:41

From what I've heard a lot of the risk with cvs relates to the experience and expertise of the person who is carrying it out and that with a 'good operator' the risk is reduced to the same level as an amnio. How you ensure that the person carrying out the cvs is 'good' or as good as they can be may however be difficult. I also heard that trans-abdominal cvs is 'safer' that trans-cervical cvs although I don't know how true this is.
Also cvs needn't be painful. I had cvs at 12 weeks and can honestly say I felt no pain whatsoever. I've never had an amnio so can't say what that would be like.
As Ghosty says I think a lot of the decision whether to have amnio or cvs depends of what you would do if you had a 'bad' result. If you would have the baby regardless then what is the point in going through any process with a risk of miscarriage.

Rhubarb Fri 08-Aug-03 17:47:25

I think there is something a little wrong when you start worrying about a pregnancy that has not happened yet. Linnet - I hope you don't mind my asking, but is the thoughts of pregnancy beginning to invade your normal life? Do you eat, sleep and dream pregnancy? Why is getting pregnant so important to you at this stage?

My advice would be to enjoy your life and your relationships with your partner and child. Enjoy the process of trying to get pregnant. Make the most of your life now before you start to experience pregnancy symptoms and all that comes with it! Take folic acid, eat sensibly and relax. If you do get pregnant, then you can think about all these things and discuss them with your midwife. But wait until that happens before you worry about it!

Linnet Fri 08-Aug-03 23:45:31

Rhubarb, No my normal life is not being invaded and I don't eat, sleep and dream pregnancy.

I don't quite understand what you mean when you say "Why is getting pregnant so important to you at this stage?"
Getting pregnant at this stage is important to us because we have decided that we want to have another baby and this month is the first month that we are seriously TTC.
It has taken my Dh and I nearly 6 years to decide to have another baby and it wasn't a decision taken lightly. We have talked over the pro's and cons of having another child, I've talked to my Dr about it all, going over what happened last time etc. She put me on a course of Folic Acid and we have now started actively trying and hopefully things will go smoothly from now on.

I have friends who have had children since I had my dd. Some of them have encountered situations that made me realise that when I was younger I didn't really know as much about pregnancy/birth as I do now. I'm hopeful that my future pregnancy will be straighforward with no problems but we are discussing our feelings towards certain tests/situations etc so that we both know where we stand when the time comes. We feel that it would be better to know how the other feels about things before we actually get to that point so that we are clear in our minds about what to do or not to do etc.

I'm not overly worried and I don't lose sleep over it but there is always a little doubt at the back of my mind that everything went fine last time so this time might not be so easy. I suppose you could call it paranoia but we are happy to discuss things between ourselves and when the time comes obviously we will discuss it with a midwife/Dr.

arabella2 Sat 09-Aug-03 12:44:43

I would like to add that the triple test can be highly misleading - you can have a very high result for downs (1 in 10 is what I had with ds) and then have the amnio which shows that your baby is ok (as was the case with ds), OR you can have an ok result for downs and still have a baby with the condition. For me it is a pointless test that caused me a lot of heartache. I only had the amnio because I wanted to know whether we would have to bring up a downs syndrome child, not because I would have had a termination. I am now pregnant again and will not be having ANY tests done this time apart from the 20 week scan and I am 34 years old. I can't say anything about the nuchal fold test as I know very little about it. The whole pregnancy thing is scary if you think too much about it in my opinion but I am trying not to!!! Last time I was amazed that ds came out as perfect as he did but he did! I also cannot believe I put him through an amnio and will never be doing that again. There are much worse conditions than downs or spina bifida where I would probably consider a termination but only if you could find out in the first few weeks but you can't so that's out! I'd say to relax and that you are a young and sprightly thing.

eidsvold Sat 09-Aug-03 13:58:22

I did not have a triple test as I looked into it quite thoroughly ( along wiht other antenatal tests) The triple test is about 42% accurate and I personally felt it was unnecessary.( personal reasons - felt i was being made to have too many tests and too much prodding - prior to heart condition being found etc)

My dd has down's syndrome - suggested by the 20 week scan which picked up a cardiac problem - further confirmed by a fetal cardiac scan at 22 weeks. That cardiac condition is very common in children with down's syndrome and we were offered an amnio - given that my baby hated any interference ( including ultrasounds) and that it would not make any difference - we did not have an amnio. Even though we would have had the amnio at Harris Birthright Trust - Leading hopsital in antenatal testing etc - I was not prepared to risk losing my baby. The cardiologist was very supportive and said that if it would not make any difference to the outcome ie we would not terminate - then we should not have the test.

I know that next time I will again refuse the triple test and an amnio and cvs and probably nuchal fold even though I now have an increased risk of having another child with down's syndrome without taking my age into account as well. ( will be over 35 when we have another baby)

Ghosty is right - statistics from Prof. Kyriades ( SP?) is that 3/4 of babies miscarried because of amnios are 'healthy' babies. So while the risk may be small in terms of the outcome there ... I guess you have to weigh up your options.

In terms of information - do a search on Harris Birth right trust or on amniocentesis and you should find a lot of information - that is how I found my information . I think I also searched on google for antenatal tests.


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