to tell (the boss) or not to tell?

Ok well obviously I'm going to have to tell at some point - the question is have I reached that point? I was planning on waiting until after April 2nd (my second Drs visit where they will do another ultrasound and confirm that everything is going normally - marking the end of my 1st trimester) but recently a rumor has been going around work someone we work with is pregnant. After my initial reaction (what? she's having another kid??? The one she has is barely over 1!) my thoughts went to myself, of course, and how this effects me (does this mean there'll be less breaks for me since we're in a tight economy and we can barely get photocopies done without getting the third degree?). See I work in a place that has a parental leave policy....but...it's up to the discretion of the director how that will look. Meaning, I have no idea what I'm going to get. Plus, we are hiring a new director in the fall and the one we have is retiring so it may be a mute point anyway since she may say to me I'll have to wait until we hire someone in the fall to find out my fate. Despite my co-worker getting pregnant it's not like people have babies everyday around here (in fact, she's the only one in recent history) so there's not a real precedent for what happens - and now that we are broker than broke it's really hard to compare it to anything in the past anyway. So....what do you think I should do? Should I still wait until after my Drs appointment to talk to her about it? Or should I talk to her now so I get in on whatever she may be promising to preggo girl #1?