The risks associated with this extended testing are just not worth it, perhaps aside from Down's (from a numbers point of view). Even then, there are many completely gorgeous children and people with Down's .. chances are you'll have a curveball in life one way or another at any rate.
I have two children, one diagnosed with ADHD/ASD, the other likely not too different but too early to tell. Apple doesn't fall too far from the tree. Wouldn't change a thing, other than to avoid the ABA services companies like plague - they prey on your insecurities and you might face financial ruin for possibly no real benefit to the child if you go along with their spiels.
So, to see medical companies exploiting vulnerable new parents who will do anything for their children? I am shocked. (/S...)