After reading Ian May's books, I am convience that I was "fearful" of the labor and delivery in a hospital. She states in her books that a woman could be in transition, get to the hospital and find she is only 3 or 4 cm dialated or that labor completely stopped. It wasn't that the woman wasn't in transition at 8 cm, she regressed.
My own situation was slightly different, but still intervention was started b/c my labor was not normal. My waterbroke and I had no contractions, if I had the option of a hb like I wanted I don't believe I would have stalled. I believe that fear of the hospital kept my body from doing what it was suppose to do minus drugs. For me I dialated on Pit and pushed for nearly 3 hours, the baby wasn't dropping (of course, I'd been strapped to a bed on EFM and told not to move). I wish I had never gone to the hospital when my water broke like they tell you to. I wish a lot of things different... You just don't know what you are getting yourself into until you are there for the first time, all the best planning in the world isn't enough when you don't know what and who you are dealing with.
It is possible that many woman are not comfortable with hospitals and the unknowns once you arrive. Labors stop in animals when they are in danger, labor is primal, it is only reasonable to think this can happen to women as well.