I told my family when I was six weeks, as I went home for my sister's wedding and knew that they would know when they say I was driving to the wedding and offering others lifts. Otherwise I would have been getting a lift or a taxi!! My family know me too well!
I told my boss at eight weeks as she was getting right into telling me what long term projects I would be working on when back at work full time ( I am still on maternity leave with first bub, working two days per week). Her reaction was to laugh rather hysterically!!