Oh, keep it to yourself if you can!!!! We had to tell family as i went into labour a couple of weeks early - on Christmas eve. And everyone was supposed to be at mine on Christmas day. So we called round expecting a quick call "don't turn up tomorrow, we probably wont be here, or if we are, I wont be providing a full christmas dinner!" but the stress from my parents was so annoying!!
They called again and again and again when I was trying to labour nicely at home as long as I could (in 'their day' I would have been in a nice sensible hospital bed so keep listening to DH tell them I was fine and he wasn't running any risks with my health 'for these new silly ideas' - time I wanted him with me). Then when I was in hospital, my mobile kept beeping from yet another text, which got me stressed as I felt like I didn't want to have to say how far dilated my cervix was to my dad... Then when I ignored them, DH's phone kept going.
Then when DS arrived, they wanted to be there straight away (by this time, I wanted to sleep and told DH to tell them to leave me until the following day - it would have been close to 8pm by the time they could have got there, having been in labour for 27 hours before this I don't think it was unreasonable to ask them to let me sleep) so they called the hosptial to find out visiting times so they could come anyway... it took a dump of snow closing the roads to delay them a couple of days, which is handy as by that point DH and I had both calmed down from being pissed off with them for adding extra stress.
When they did arrive, I had had some complications and was in a bit of a bad way, but they were fussing round the baby and stopping the nurses who were trying to stick drips in me.
PIL on the other hand, didn't contact us until DH called to say DS was here, then sent a text the next day asking if they could visit, then MIL threw FIL out of my room when she saw the doctor coming to see me as "that girl needs a bit of privacy". Oh, and they brought me chocolate. I'd had a bit of a difficult relationship with PIL prior to this, I've rather loved them ever since.