The normalcy of the introduction and the oddity of that huge, pregnant belly on what would otherwise be a skinny slip of a man clash absurdly, and for a moment she fears she might laugh (which would be horrible), or faint (which would be worse). In the end, she does neither; manners dictate an automatic, "I'm Greta--Greta Baker," and she forces herself to look back up at his face as she returns the handshake. Well, at least she's not going mad. He sees it, too.

She releases his hand a little belatedly, then - sorry, but she can't stop staring. "H…how? Sorry, I've just never--" oh, she is almost certainly being rude, and she winces apologetically. Say something appropriate, for god's sake. "Um. Congratulations?"