I think SA has the same 10 week rule. Our organisation's maternity policy states that they would prefer to know straight away (especially for people who work with residents - I'm in aged care) so that those whose jobs need to be changed a bit for safety reasons can have the changes put in place for their safety ASAP. (I work in the head office so my duties wouldn't need to change). Everyone at my work knows that I'm TTC so any time I've been off sick I get all the questions when I get back 'are you pregnant yet?'