Kenobi would've had to know; or else, how would he have hid them?
Obviously, none of the others knew, I think, because Vader had no clue. And he had killed majority of the Jedi before them, so most likely, he asked, er, forced, information out of them.
That's my theory, anyway--the council has no idea.
I think they probably don't know she's pregnant. And if they do, they'd think it common that a senator has children. Maybe they don't know that Anakin is the father. Well, that's my opinion. However, I read somewhere that Luke (in a novel) felt Leia's twin babies when she was pregnant by using the force. Is it true? And then could the jedi council members do the same?