I've told a few clolse friends and the company after I was diagnosed/confirmed pregnant (I think that was 7.5 weeks). I didn't tell my parents till I've done the Oscar test as I don't know if the baby will still be hanging around and/or having any defect that i have to give it up. It is more for the reason I don't have to explain things to others if i have to give up the baby for health reason.
I had no choice.. because i need to take sick leave before 12 week..
and actually, even i had not said anything.. everyone knows I am pregnant! ppl give seat to me from 8wk!