On the Fashion Sense of Sarah, Isaac's mother

I love this very odd image of Sarah, Abraham's wife and Isaac's mother, by the Flemish engraver Hans Collaert (1545–1628). This image is mentioned in passing in my novel The Bride Stripped Bare By Her Bachelors, Even, which revolves in part around the story of Abraham and Isaac. I just cannot figure out what she is wearing, but I think it is a fashion faux pas. Call me a moderne, but I'd cover that belly, pull up the front of the dress, and not wear squares on my breasts.