From an email discussion on waterbirth (Karil Daniels) writes:

"Does anyone have any statistical information on the value of waterbirth to prevent or lessen tearing? If not statistics, any personal information?"

Marla responds:

"I can give you a personal experience: 1st baby born out of water, 4.5 lbs - episiotomy (!); second baby born out of water, 5.2 lbs, 1st degree tear + one insignificant tear (multiple presentation, though); third baby, born in water, 7.4 lbs, no tear, scratch, anything."