In my opinion, creating life is basically creating need for the sake of need. The unborn cannot suffer, want, or need. I'm an antinatalist but it's not my job to tell people not to have kids.
This case just seems wrong to me. It's not like you're having the child because you want to be a mother. Why reproduce knowing you will CTB? Knowing the suffering that comes with life, do you really want to impose suffering on someone else?
Please rethink this. Like I said, abortion is really the only ethical choice I can see in this scenario.