QUOTE (Penguin78 @ 05/08/2012, 08:39 AM)
Just to clear up some misinformation above.
The high HCG, low Papp-a has been found to be another indication for Downs and has been known to pick up more instances of Downs then just thr nuchal fold and nose measurement. So just because those measurements were good, does not discount the high risk shown in the bloods.
So I know this isn't helpful news to the OP, however, as has been mentioned the particular blood result can also indicate problems with baby weight, blood pressure etc so if you do get the all clear from the amino, they will monitor those things a bit closer then normal.
I had a 1:34 chance of Downs because of my bloods. A CVS came back all clear, but I did end up with pre-eclampsia. So it was good they monitored my blood pressure.
It is true that low PAPPA and high HCG pick up downs syndrome but it is usually in cases where the nuchal fold and nasal bone presence are not good as well. The majority of cases where the bloods aren't good and the scan are good are usually not the '1'
That being said, the test are all about statistics and averages and there are cases where the nuchal fold has been small and the nasal bone appeared 'present' yet the child had chromosnal abnormalities.
OP - not that I'm trying to discourage you from having an amnio (I had one after weighing up my risks and the need to know) just make sure you understand the risk of having an amnio.
in your last post you said that the OB said that it is a 'small risk'
The current Australia wide risk is about 1:250 (so the risk is actually higher than your NT result risk) of a miscarriage and depending on the place where you have your amnio done the risk can be higher or lower than that. The risk is purely based on 'user error' - so the experience of the person doing your amnio. The US clinic I had mine done said that based on their own clinics statistics their risk was close to 1:400 (better than my 1:32 risk) and they did the procedure at least twice a week which I was comfortable with.