goodness you poor thing- MIL are pains aren't they. big hugs to you.

i would just say the hospital has a policy that only 2 people be allowed in. so you DH and your mum.
to be honest- i would just be straight with her and say she makes you uncomfortable and since she has made it obvious she does not want the baby- she is onot to be invloved either way. i did this with my MIL recently and it has sunk in now- she has finally realised tht i wont take her crap and am going to stand up for myself.

swetie, it's not good for you to be stressing like this not good for you and bubs, i would make sure you DH sticks by you too.