I can just see a film version in my head - Shane Meadows meets David Cronenberg. Probably wouldn't reveal a money shot of Mary until the very end, just suggestive close-crops of various bulges and pustules to hint at her deterioration. Very minimal, no-fuss CGI, Cast kids who are genuinely that age (and not early 20s), and a hand-picked, minimal, creepy as fuck soundtrack featuring the likes of Tortoise and Boards of Canada.
It could be REAALLLY Good.