Satya's right on the nut.

My risk was 1:2 - REALLY bad.

I had the amnio and the worst part of the whole procedure was waiting two weeks for the results. Even with my very high risk, it all came back fine and the baby does not have DS.

I would recommend an amnio to anyone. They look and sound bad, but they're really not that awful. You just have to ensure you take it very easy for a couple of days afterwards. I took three days off work just to be sure.

It's all about your sister's personal choice. Her odds seem very good to me - well, compared to how mine were anyway.