Hmmm...well, it's never happened, but if I had ever had a one night stand and the woman called me up eight weeks later saying she was pregnant, the only Carlin sketch I can think of that would relate is the "Seven Words You Can't Say" bit.
Ring... ring...
Hello?
Hello, this is Jaaaaane.
Jane? Jane... who?
Jaaaaaaaaane.
Jane.... Jane?
Yeah, remember? You met me at a party about 6 to 8 weeks ago? You said I was a reeeeally good sport?
Oh, geeze... that Jane. Oh, yeah, well... Jane, how are you?
Pregnant. And I feel like I want to jump out the window!
Say, Jane, you really ARE a good sport, aren't you...
***I think this was from the FM & AM album (just before Class Clown)***