Alice Turner from Your Doula Bag has written a great blog post about using the shower as a pain coping method in labor. I have seen laboring moms use the shower with great success in helping to deal with their pain from contractions and to relax during labor.
Although I never quite made it into the shower for my labor with my son, I am definitely going to try it for any future labors. The shower is my go to remedy for anytime I have a migraine, back ache, or other illness so I fully believe in using it in labor. You can read Alice's article on the topic HERE.