A girl I know was in her late 30s when pg with her last bub (IVF) and had a 1:10 risk from the NT/bloods, she had the amnio and it was fine! Baby is now a healthy little boy. So take heart.
My obs said the risk of m/c with an amnio is 1:400, my risk with DS after the testing was 1:850 (I was 39) so we didn't have the amnio.