Hi feelingbroken,
I'd like to welcome you to bpdfamily. I'm sorry that you're going through this. BPD behaviors are more apparent during periods where the person is going through a lot of stress. BPD is also an emotional dysregulation disorder, where the person cannot regulate their emotions or self sooth, it takes a pwBPD much longer to return to their emotional baseline of happiness. I can just imagine how pregnancy effects a woman's hormones, your daughter' is going through right now, it could ne that she feels out of control inside so she'll try to over control her environment to stabilize her feelings.
Also a pwBPD are hyper sensitive to rejection and are constantly on the look out for rejection, real or perceived. This is just my personal opinion but I seldom use my phone unless I have to, i'll send a message on Facebook messenger, text or email. This is just my guess, I think that she could have thought that you didn't want to talk to her on the phone and maybe she thought that you were avoiding her. It's extreme for you and I, but to person with BPD it's hurtful, pwBPD hate being rejected.
If I were in your shoes for this incident, i'd let it pass and not say anything because a pwBPD cycle though moods rapidly and are so into each mood state that they forget what it's like being in another state. Certainly we can help, there's a ton of tools and reading materials here on the site that works with a pwBPD and you can transfer those tools to other r/s's in life.