Do you mean, like for good? Or all night long? Ladies, if you haven't hit the good ol' change yet, you're in for a rude surprise. With it comes waking up, oh say about every 2-4 hrs. It's almost as bad as having to get up for the newborn feedings!
So, to answer your question...I try very hard to make it 'til 6, but it's usually about 5. For no darned good reason. Grrrr.