Hi,
Coming from the point of view of someone who had two homebirths, I can say I am not convinced that water births are totally safe. Of course, nothing is totally safe in life, but I have read things about water births that made me a bit weary. I actually labored in my bath tub for a while, and it was great for pain relief. If your hospital has a labor tub, they will probably encourage you to use it during labor but require you to get out for the actual birth.
I was concerned about two things – generally, water birth advocates say that the baby doesn't start breathing until she reaches dry land, but if the temperature of the bath water is a lot different than the amniotic fluid, the baby may be shocked into breathing before she gets out of the water. The other concern is that the water can become quite dirty during labor and birth. There are stories of midwives who just "fish" fecal matter out of birth tubs with a net, and then just leave the baby to be born there. Just because you got most of it out, doesn't mean there's not bacteria; right?
Just my thoughts!
Olivia