I just wanted to add, that I used gas and air in my labour with DS, and it very much did take the pain away. I was hesitant to use it as I could possible imaging that it would do anything for me, and had only read people saying it made them throw up - I didnt BTW.

I had gas for about 30-40 minutes Id say, and in that time I went from 4cm dilated to 10cm and ready to push.

Prior to that I used water (bath) and that made a huge difference as well.