Hi Kate - I think the other girls have made good comments. But I also wanted to let you know not to worry about being self conscious in labour. My MIL was my midwife and I remember saying to her before not to look at my ...cellulite, chubby thighs etc. She laughed and said "Darling that is the last thing you will be thinking of when you are in labour". And boy was she so right.
Birth comes naturally but it does take all of your focus. That is why it is good to have someone focusing on the other stuff eg. giving you sips of water, helping you to the toilet if you need, massaging your back, or just sitting in the corner if thats what you want. But it is good to have someone who knows what you want and need and who will be there for you. Even if it is just in case.
I hope this helps.