My mw looks for a big hormone surge about 37 weeks. Kind of like you are back in first trimester feeling out of sorts physically.
I go past my edd so I get pretty pissy with the constant "still no baby." Considering I have been pg for three years I am already sick of it so who knows what will happen when this summer hits!!
And, as others have alluded to, birthing is when we go within ourselves so all those people around just don't help. Unless they can spend 24/7 rubbing, massaging and keeping the bath warm and full leave me alone!