I felt the same during the last few days - constantly struggling for breath - but it was not a problem at the birth - believe me you will have other things on your mind, and if you are going to be in hospital, they will react promptly if you or the baby are unwell. However, judging for the 3 messages you have posted on this site, it sounds like you are very anxious at the thought of the birth, and you should mention this to the midwife/gp and see whether they can let you see a counsellor.