Hello Angry girl,
I read all of your posts and can relate just by the name you've given yourself.
I have a similar situation with my Nmother and her family. I don't have children, but anytime that something noteworthy has happened in my life (mortgate got approved, dealt with clinical depression, had to put my dog to sleep, bought myself a horse, etc., etc.) my Nmother is not there and if I mention anything of note to her about my life, I get a very blase' attitude and vague comment about it. She has also alienated her family against me as well and because of it, my grandmother and uncles have nothing to do with me either, and it's not for a lack of trying on my part.
I can tell you not to feel guilty, but you have to work on that yourself. It's a hard pill to swallow, but why should you feel guilty about people who do not care to contact you? And what kind of mother doesn't even acknowledge the birth of her own grandchild? I could totally see my Nmother doing the same if I had a child. I haven't talked to my nmother in close to a year and it has been the healthiest year so far in my 35 years. Don't let these people get to you like this. I can only tell you to stay away from them and most everyone will too, but only you can make those decisions. As far as having your child know his grandparents, sure in a normal family you would encourage that. Do you really want your child exposed to the same BS you've been exposed to all your life?