I don't think the problem is with telling them about your pg but with what they have to say about it. I would tell them when it is convenient for you but I would not stress myself out needlessly hiding it from them. When they find out, you will just have to be quick to draw the line on what you are willing to take from them. Those lines need to be in place anyway with everything your family decides to do when it comes to people like that. It took us awhile to figure that out (during my pg with my 3rd child as well actually) but once we laid down the law with certain family members they either keep it to themselves or talk about it behind our backs, I guess. FIne with me as long as I don't have to keep defending out decisions or hearing any crap about them. If they can't do that, I would cut off contact until they can. Good luck!