Do you say “we are pregnant” or “I’m pregnant” ?

I noticed a lot of people now say “we are pregnant” referring to them and their SO/ father of the baby. I was with a friend and another friend posted a pregnancy announcement online she said “we are pregnant” talking about her and her husband. The friend I was with was saying how it’s so annoying and dumb to her when people say “we”instead of “I’m”. I think it’s cute because even though the women is really the only one pregnant it really includes the man since it’s his pregnancy too kind of. I think my friend might be a little bitter because she is pregnant from a one night stand and the guy doesn’t want to be involved.