When it's hopefully my turn, I plan on telling my parents right away because if anything (God forbid) should go wrong I would want them there for support (and they're not the sort of parents who fuss anyway). I'd also tell some close friends right away for the same reason. But with the PIL I'm gonna wait as long as humanly possible (and I think DH will agree with me) because they are the biggest fuss pots ever and if something were to go wrong they wouldn't be much support.