Not sure if this happens in all States but i know here in Perth if you want to terminate after 19wks it has to go in a board of ppl and it's up to them if you are able to go ahead with it.

I was going to wait for the 19wks scan instead of having the amnio and i am glad i went with the amnio as they couldn.t see how well the heart was when i went at 20wks for the next scan so i ahd to go back 4wks later. I was also told my my counsellor that they don't always pick up markers at 20wks as some babies might not have downs but could still have a hole in the heart.

I would talk more to your counsellor and DP as your risk factor isn't high risk at all.