Quoting Mother of amazing kids:" In my opinion I think she is telling you that she doesn't want the baby because she don't want to get ... [snip!] ... it gets better over time, it sounds like you really love her. Just be there for her that's what she needs right now. Good luck."
Thats what I was going to say, She has lost in one way or another two babies, I would imagine she is scared and feeling alone right now, if she is living with her grandparents she might not be able to talk to them about it all, I would try and talk to her properly face to face and reassure her that you WILL be there no matter what. I hope you get sorted OP