Week 16 tests ... talk to me please!

[Litterbug]

Hiya,

I had these with DS1 3 years ago and the results came back 1 in 25,000!

I opted out of them with DS2, I just didn't feel the need to have them.

So when it came up this time at my 12 week appointment I just automatically refused them.

However, as I approach 16 weeks I'm not sure if I should have them.

Its correct that they are just results that give you a rough idea of the chances something is wrong. So nothing is definite right?

What are the results based on?

Age? Previous pregnancies?

And If my first pregnancies results were very, very low at 1 in 25,000 and both my children were born healthily and normally surely if they are based on age ect ... then the results wont be that different 3 years down the line? (am 24 btw)

Thanks x

I am not very up on the science but roughly speaking the tests done on the NHS at 16 weeks look at a number of markers in your blood - they compare certain hormone levels with what is expected in a "normal" pregnancy. Babies carrying Downs or Edwards Syndrome can show up as a pregnancy with the abnormal levels of these hormones and the results can be anything from 1:2 to 1:50,000.

They are only screening tests and cannot give a definitive answer either way - only indicate whether it is likely there may be a problem. I believe that your age is part of the calculation as risk increases with age. I don't think previous pregnancy is a factor unless you had a problem in a previous pregnancy which would be taken into account.

Obviously age is not a risk factor for you but this and the previous healthy pregnancies alone would not totally discount the risk of a problem in this pregnancy.

Essentially it is a decision that only you and your partner can make - based on whether you would want to know if there is a problem and whether you would do anything if a problem was discovered. I'm sure its not too late to change your mind - if that is what you want to do.

Hi I'm not an expert at all but just thought I would post my thoughts. As I understand the nuchal scan/bloods test take a combination of factors to give you a 1 in X probability. They take your blood, measure the nuchal fold (muscle at the back of the neck) and the mothers age. So I guess it could be different in each pregnancy, especially as you are a bit older now (when the odds go up) although as you are only 24 they won't be very high at all, based on age. That doesn't mean they will go up or anything but that is one of the factors. I don't know if previous pregnancies have any influence.

It is not a guaranteed test, just a probability.

Also you can only have the nuchal scan / bloods at between 11 weeks - 13+2 weeks so it would be a bit late for you now and I think the only test available would be the amnio which does have a risk of miscarriage.

Sorry if this all sounds very clinical but just trying to write down what I remember.

Do you know what you would do if you had a high probability? If the answer is nothing then I don't see why you would have the test. However saying that if the answer is yes remember your previous results have been low and the risk of downs syndrome is a low risk.

I hope this has helped - whatever you decide I hope you have a happy and healthy baby!

I decided against these tests, on the basis that I wouldn't do anything about the results (as chocorange said), but only you can decide that. What swung it for me was reading in my NHS book that 1 in 4 babies born with downs are not picked up by the tests anyway, so I could get low risk and the baby could still have downs - it just seemed too vague for me.

I would discuss it further with the MW or doctor, as like mrsboogie and chocorange I'm not 100% on the facts, so they'll know much better than me

All the best

Z

Hmmm, thanks.

I think I still feel the same as with my last pregnancy, that I don't want them. I think I just had a bit of a wobble!

Thank you.