We had the NT scan done and we were given a high risk result with the downs syndrome (1 in 141 chance). The scan was actually looking ok, but apparently it was mainly the blood results that brought us down. We were booked to have an CVS - but the day before I decided not to a I knew I couldn't terminate. There is other little indicators they can see at the 20week scan - and most were ok at our scans (we also had a 30week - just to be sure). Turned out we were NOT that 1 in 141 - we now have a healthy little boy.
In saying that, I would probably still do the scan again...cause there are a few other things they look for. My cousin had her scan done and it turned out that the baby was not ok and that it wouldn't survive - so they could terminate early (still hard I know, but could've been even harder if they'd found out those results further down the track).
I also loved the opportunity to see our little one.
Good luck making your decision...obviously it'll come down to what feels right for you.

