Pregnancy Superstitions?

My firends just got pregnant and she took 7 at home tests and told everyone after only taking those at home tests. This was a little over a week ago. She just made her doc. app. isnt it bad luck to tell before a certain part of your prenancy? I tried to explain to her not to spread the news to everyone b4 the doctor visit cause what if its a false alarm. How long should you wait to tell people???? Expecially people that really want you to get pregnant (Her in-laws)