I too wouldn't be telling people I was in labour. Our close freinds let us know when their labour started but they had complications and she had a 36 hour labour and of course naturally (and rightly) didn't update us with what was happening so we were always thinking the worst had happened etc. And I imagine there'd be an extra expectation on you as the labouring woman to hurry up adn get it finished so everyone waitign can breathe a sigh of relief and charge in!