Strongbird I would give it serious thought before you do or don't. I told my Dad and his wife and they cried. I didn't expect that reaction and I was like, "I don't have cancer and I'm dealing with this." They just have this black cloud over them about me having to deal with this disease the rest of my life. I can think of worse things personally.
I didn't tell my in laws and they were here a week. I didn't drink while visiting with them back in October and just told them I was concerned about my blood pressure and my health in general. Over this past visit I was asked nightly if I wanted a glass of wine with them. I finally said, "I'm with child." The room went dead and I started laughing. They didn't ask me again.
Many ways to go about it, but I would think long and hard when it comes to telling your Mom. I'm sure you will do that any ways.