Hello Discardedman27!
Welcome to the BPD family!
I'm sorry for what you're going through. Being split black by a loved one with BPD is incredibly painful and bewildering. So is being cut out of that person's life.
I don't have experience with the pregnancy angle, but I do know what it's like to be in a volatile relationship with a pwBPD.
She's discarded you and hasn't shown any hope or interest in renewing the relationship, is that right? Has she ever done something like this before?
Unfortunately, if one party isn't interested in a relationship, there's really not anything the other party can do about it. A pregnancy does complicate things. I'm not sure what legal rights you might have there regarding your unborn child, but other members may have more experience or you might want to ask a lawyer.