I don't remember exactly, but the second time it was in around 1:370 - with a combined result of around 470. The first blood test was done at 15w0d (pretty much the first day you can do the test here) and the second one was 16w6d. (Here in Belgium they deo a nuchal measurement on w 12-14 and a "triple" blood test at 15-18 weeks and give you a combined probability based on those two, plus the age. The cut-off for high risk is 1:250.
The second doctor I went to was a pretty old professor and he told me that he's seen lots of "high risk" results, but out of those not one positive Down-case in his carrier. We didn't want to risk the amnio, as it took us a long time to get pregnant and probably would have kept the baby anyways. But I read up a lot on these "tests" and I am not at all convinced about their usefulness. It seems to me more like the probability statistics insurance companies use to calculate how long you are going to live - it takes patterns, and tries to draw conclusions as to the individual.
Also the cut-off rates are pretty high as testing is fairly cheap, while a baby with Downs is likely to cost more to social security if he or she is left to be born. That's why the doctors push for amnio and termination and give as little information to parents as possible. I'm sorry about the rant, but when I read up on the subject, I found this practice really apalling. And as a person, who has gone through a pregnancy with supposedly "high-risk" result, it can really suck out a lot of joy of the experience...
