The clear impression I got when I was studying Hypnobabies is that instinctive vocalization is good if it helps you. They actually call the type of pushing they advocate "Gentle Ahhhh Pushing," which is not the"Breathing the Baby Out" that I read about in Hypnobirthing by Marie Mongan (which I, for one, find confusing) nor is it the provider-directed prolonged breath holding of the Valsalva("purple pushing") method. Hypnobabies advocates pushing when and as long as feels right, and says that your instincts will guide you to you use breathing, vocalizing, holding your breath, or some combination of these. The Hypnobabies materials explain that many women instinctively vocalize with an "ahhhhh" sound when they start to feel their babies moving down. This is what I did, and having read that, I was not afraid to do so.
Hypnobabies actually doesn't teach that being quiet is the only way to have a good birth, but I think there may be some contribution to the idealization of quiet birth with the videos that are used to promote it. While videos of quiet birthers do a good job of showing one type of birth that is possible with hypnosis (and I believe possibly more common with hypnosis than without it), they may not necessarily show the whole spectrum of what a good birth with hypnosis can look like. I looked through the Hypnobabies birth videos that I could find online. A few did not include video of pushing (totally understandable if the video shows the baby emerging and you don't want your "bits" on the internet!). Of those that did, there were some where the mama was mostly quiet during pushing, but they were not all like that.
Sierra's Hypnobabies Homebirth video shows her "ahhh" moaning transforming into a powerful roar as the baby is born, and is beautiful.
I think that if I had the freedom to follow my body's instincts instead of being instructed to not push and later, to hold my breath, I can see how making birthing sounds similar to Sierra's would likely have come quite naturally to me. I hope that when I am a Hypnobabies instructor, that I will be able to help my students know that being loud (or having the expulsive reflex trigger an "out of control" feeling, like I talked about in Part 1) is not failure. I want then to know that what happens to your body when you give birth is incredibly powerful. While for some women, the best way to respond to the power may be to be quiet and focused the whole time, others may find at some point that it helps to release some of the power with their voices (I would be surprised if I am not one of these!), and this is okay. In fact, it is more than okay. It is another wonderful way to give birth.