I told my grandma about the pregnancy in a Thanksgiving card (this may seem weird, but we never talk on the phone). She sent me a birthday card that said "Good luck on your venture."
I told a man that is a grandfather figure (Poppa I call him) in a Christmas card. He called home on Friday while I was at work and left a voice mail that said "Congratulations on your event."
It's a lot for them the take in. I'm a lot for them to take in. But at least they are saying positive things, even if they can't bring themselves to say "Congrats on your pregnancy" like most people do.