My doctor suggested something that I'm not quite comfortable with.?

I am 28wks pregnant and a I have to see a high risk doctor because last year I delivered a stillborn baby. I have had tons of ultrasounds and the doctor said that so far everything looks good. She wants to do this procedure(forgot the name) where she inserts this needle into my belly to retrieve something to test for any abnormalities but the side effects may cause pre-term labor, l bleeding and much more to the point where I don't want to risk it. Have anyone had this precedure done or know anyone who has?