I have a theory - that the last week of pregnancy is like your child's late adolescence. Nature makes the experience as horrific for you as possible to make it easier to let go and kick them out of the nest/uterus. You go into labour totally psyched and unconflicted and willing to put up with anything to end the misery.

This year I've "encouraged" one child to leave home, and soon I'll be expelling one from my womb, so I guess it's given me an odd perspective
I like it