Verbally Abusive Mother

Jordan
Hey all....So I'm 28, no children yet, not married, been with my SO for 2 years and we live together, we both work, blah blah blah....long story short I'm nervous to break the news to my mother that I may be pregnant/TTC. She has a very bad history of calling me out of my name, talking bad about my boyfriend, etc. See my mother is the type of woman that talks about all these people at her job, unwed mothers to be, women having multiple pregnancies, and such. But if it happens to her own (FYI I'm her ONLY child) she would have a full on conniption. She digs herself in holes and brags on me so much that she doesn't think about if her own child is to make a decision she doesn't agree with that it would "make her look bad" bc she's placed me so high and holy. I guess my issue is if she's upset, be upset and away from me. But don't put your shit to the side once the baby gets here and be okay after 9 months of stressing me out, telling me what she's not going to do, how this is such a disappointment yada yada yada....and then be all goo goo when the baby is here. In my world that's not how it works....what do I need to do to ensure that she won't flip the f*** out on me when I tell her. For Christ sakes I'm 28 years old!!!!