workplace problems!

So one of my co workers is known as a "bully". She's 37 and I'm 21.  I've never had any problems with her until recently, she said a few rude things which I ignored. Now she's trying to bump into me on purpose, it has happened on several occasions. Each time I try to avoid her she intentionally tries to walk in my direction and shove and bump me. Keep in mind I'm 7 months pregnant and I don't want my baby to get harmed. What should I do?