But in the same book Joey and Freida have a fairly frank chat about Bernhilda clearly being on the verge of giving birth!
I don't actually find it that weird - Sybil is apparently two months early (
) and even assuming that back then they had much less accurate ways of measuring these things, and Sybil was not actually born at 7 months, I'd assume that Madge looked far less pregnant than she was, and Sybil was definitely premature even if not quite two months premature. Joey is away from the Sonnalpe all term, except for one visit where she only sees Madge for a short while.
To me it's more weird that Madge doesn't just tell Joey, other than by 'hinting'.