Maybe she is just not ready yet many women go past there due date. At my last appointment with my 2nd baby she hadn't drop nothing no dilation aor anything. But the early early morning of my due date she was ready . I didn't even think I was going in labor. I didn't feel any contractions before going to bed nothing. I just woke up alot in the middle of the night I didn't think anything of it. Until I noticed I had got up 15 min earlier. So I laid there for a few min an felt a contraction . By the time I got to the hospital I was a 8. She came super quick. An as for the down syndrome as long as all ur testing came back good I wouldn't be concerned. Babies come wen there ready not wen dr think they should.