this happens with people that are just ignorant about themselves and their bodies. go look up 'i didn't know i was pregnant' and you'll see a lot of cases where women didn't become huge landwhales. hell, i had people thinking i'd just gained a few pounds when i was 9 months pregnant because i carried so far back in my body, i didn't have that protruding belly. some people just don't 'look' pregnant. and when you add ignorance about their own bodies into it or varied symptoms... you get surprise deliveries in bathrooms.