I'm a teacher and unfortunately my attempts not to tell anyone failled miserably due to thefact that I had to throw up all day in the staff toilets (adjacent to the lunch room) and I am not a quite vomiter. Added to this was the fact that I had to tell my principal and teaching partner so they could cover my class if I had to leave in a hurry. After the second time someone walked in on me being sick the word was out but I just explained that it was very early and that I would appreciate them keeping quite until we get to 12wks and everyone was very understanding. We "announced" the pg at 12 wks to the staff and community.