I just said flat out I want an Epi as soon as I could have one, the midwife I would visit said no and harped on about crap, so I seen the social worker at the hospital and told her that my birth wishes were not being taken seriously, the social worker called the head OB of the hospital and they discussed I should go see the anesthesiologist and after that if I still wanted it I could have it. about 2 weeks before my due date the hospital (public) sent me down to talk to the anesthesiologist about risks ect and what it involved, I signed the consent form then and he attached it to my birth plan.
I was induced and when I got to 3cm I had a midwife I had never met before who said I should wait and see how I go, I just said no and that it was in my birth plan and I was within my rights to request one, I had spoken to a social worker and the anesthesiologist and the consent form was attached to my birth plan, I just said to her if I don't get it now I will send my husband down to talk to the social worker about what's happening, I had the Epi in 10 minutes later.
You just have to be firm and know your rights. If you have had bad reactions from peth in the past then don't get it!
I suffer migraines and they have given my peth in the past for them and I have had little reactions so now they only give me morphine.
Because of that I wasn't even offered peth during my labour.
I remember the anesthesiologist saying to me that we all take something for a headache so there is no problem at all in wanting to have something for when your in labour lol.
He also said gass and peth is just like eating M&Ms when your in pain.. It doesn't do much ;-)