Water is wonderful therapy for all kinds of problems. The medical community has been using water therapy for back injuries and other injuries for years. Some physical therapy units have pools and hot tubs to be used for the therapy process.
Why not for birth? Many babies are now being born into water. Water therapy is wonderful for births and especially for a hard labor or a long labor. It will help back labor as well. If you are having a long labor, perhaps the baby is slightly posterior and needs to turn. Sometimes those contractions are hard for mothers to deal with, and after they climb into the tub, they are able to relax more and that will help so the baby will turn (as they relax). Most all mothers like water therapy. If you don't want to deliver in the water, at least labor in the water.
The following photos are of one of my grand childs birth. After being in the tub, many mothers find their labor shortened. It is safe to deliver in the tub Remember that babies do not 'breath' until they take a breath of air. As long as they are under the water, their body will function just like they were in side of the uterus, in the bag of waters.
I do water births for my clients in my midwifery practice. Contact me for more information.