Mother-in-law is too clingy!!!!

The last time I went to the ER for mild cramps, she snatched my prescriptions out of my hand (she does have a pill problem). She invites herself to the appointments (we do politely decline her company) and doesn't understand my modesty. "Oh don't worry I'm gonna be at that left leg when you are delivering my grandbaby anyways!" This is our first child, I want this to be an intimate experience between the hubby and I; no one else. When I do explain this to her, she gets defensive. I get the, "I've helped deliver all of my previous grand babies and it won't stop with this one" speech. I've seen her be a grandparent and it isn't good. She smokes in the car with the children and let's them lay in their crib for a good solid hour crying their hearts out. So I'm not feeling very close with her knowing how she treats little ones. Im at my whits end about this.