There has been the question of whether it is safe to waterbirth if a woman tests positive for GBS. Does the birth pool become a breeding ground for this potentially dangerous bacteria? This possibility has been cited for hospitals not allowing women to give birth in the water. The question has an answer now that a study has been done on thousands of waterbirths. There were only 1 documented case of early GBS in a baby born in water. In fact, this shows a protective effect! In other words, you're more likely to pass GBS on to your baby in a "dry" birth. It's possible the water washes the fluids off of baby before the bacteria can "take hold" in his system.
Perhaps I can look forward to the day that a woman at my local hospitals doesn't have to get out of the water at 8 centimeters when it's helping her labor. We go into much more detail about GBS, waterbirth, and place of birth choices in my San Angelo childbirth class.