Not super controversial, but controversial for some. Do you think it’s appropriate to ask a woman if she’s pregnant?

I went to the vet today to pick up some prescription cat food and the receptionist hesitantly asked me if I’m expecting a baby. Of course I told her yes (after thinking for a split second “Say no just to fuck with her”). She then seemed relieved and then congratulated me.

But in all seriousness, I had a coworker who was constantly questioned about pregnancy. She wasn’t expecting though. I would say she’s a little bigger, but not huge. She told me she would get asked at least once a day, sometimes more than once! I thought maybe it’s because she purposely covered herself with a giant sweater because she wrapped it around her stomach and kept her arms crossed, but it’s because she was cold.

Is it appropriate to ask? Is it inappropriate? Is it appropriate only if you know that person?