Would you tell your Mother you were pregnant if she was dying?

My Mother has been given weeks to live from cancer, I've not told anyone really in my family as things are pretty sad right now. I have only Told my sister and she was angry at first, saying this would break my Mothers heart and that I cannot tell her and that I was just being selfish she can't believe I did this. She called an hour later to apologize but it doesn't really change anything. Honestly - when we tried for baby we had just gotten married and she was told 2 years to live we've been fighting cancer for a few years now so I wanted to hurry so she'd meet her grandchild (my 2nd baby) it was afterwards we found the cancer was worse and she actually has only about 6 weeks left. I think she will be sad thinking she will miss it, I'm torn. I'm leaning towards not telling her - and dreading telling my father as he is already heartbroken, this baby will be a joy and a blessing but it's hard to see at this point for them. I'm 10 weeks it's my 2nd baby and I am just starting to show already.