I didn't do hypnotherapy with my last 2 births, but they were calm. I was at home, in the pool. Midwife only arrived as I was pushing, and I was just in my own space. I did say 'can I just say, fuck this hurts' and 'can you come in, the head is crowning', but other than that I was quiet, just concentrating and breathing with the contractions with my eyes closed.
It did hurt, but I was letting my body do what it needed to and I wasn't tense at all.
I was more tense with my first birth in hospital because I didn't know what to expect, but the last two were serene. I am not sure about spiritual, but I was on a big high for days afterwards, and very proud of what my body could do.
I think not being scared is the key. However, you can't predict how you will react in labour, although being prepared is a good idea, as is yoga and being able to move and do as yur body tells you.
Best of luck - I hope you have a wonderful experience