For many women, a safe, healthy labor lasts longer than the times cited as normal, according to guidelines from the nation’s obstetricians. Giving women more time ups the odds of a vaginal delivery.
Source: Doctors Urge Patience, And Longer Labor, To Reduce C-Sections : Shots – Health News : NPR
Marlene Dotterer 
http://maisonneuve.org/article/2015/11/10/worth-risk/
Off topic but thought the above would interest you.
Wow. That leaves me speechless. Thanks for sharing it, Ann.