I have noticed a huge difference between the behavior of babies in the home births I have seen and the hospital births. The HB babies all seemed so much calmer and way more alert. The hospital babies are red and screaming and shaking. I think a lot of it has to do with the environment. Hospitals are cold and bright where at home it is warmer and usually the lights are lower.
Plus if a woman has a great support system around her, then her stress levels are going to be sooo much lower. And so what if she is vocal during birth, that is actually good, she won't be holding her breath and it will help her relax as well. It is only those around her that might see it as being bad, but it is actually a good coping techique. It is only natural to want to eliminate the pain of someone near and dear to us. As for me, I plan to be vocal. My DH is already preparing himself for being called many dirty names.