The following was reported in
The Birth Book by Dr. Sears
One study showed that women who were in the water for 30 minutes to 2
hours of labor dilated twice as fast (2-1/2 cm per hour vs 1-1/4 cm per
hour), the babies descended twice as fast, and the moms experienced less
pain.
The c-section rate was reduced by 2/3 in waterbirth moms. And water is
especially beneficial for VBAC moms. An informal study of records from
the past five years have found that use of medication (epidural or
narcotic) with waterbirth mothers was cut almost in half.