I'm 35 and will be 36 when I deliver. My midwife cautioned that the results I'll get will be "scarier" simply because of my age. That made it seem to me like the results would be skewed simply because of my age. I haven't had my test yet, and I haven't had the chance to have a full conversation with my midwife about it, so I can't say for sure.
Re: question about the nt scan