I think they mean when it's like mid/halfway through the story, like if u end the book with them happily married with kids or one of them pregnant, it makes sense, but if they have a child halfway through, the story shifts, u know what i mean? If we're talking about a whole book about pregnancy, then that's a different story, the whole book is supposed to be about them being pregnant, going to doctors visits, mood swings, body changes, etc. they can't complain about that, nor would they read that, if they have a thing against pregnancy, u know what i mean?