More and more women in the United States are using water to find comfort during labor. This is called hydrotherapy. Laboring in a tub of warm water helps women feel physically supported and keeps them warm and relaxed. Plus, it is easier for laboring women to move and find comfortable positions in the water. 
In water birthing, a woman remains in the water for delivery. The American Academy of Pediatrics has expressed concerns about delivering in water because of a lack of studies showing its safety and because of the rare but reported chance of complications. Ask your doctor or midwife if you want to know more about water birthing.