I'm responding as a mother who experienced having both a doula and an epidural.
I would never give birth without a doula.
My doula provided me with care prenatally, during labour and delivery, and post-natally, and it all was invaluable.
I could rave about her for days, but to keep from being too wordy, here's the gist:
-She visited my partner and I a few times throughout the pregnancy to talk about our philosophies, plans for birth and beyond, etc., taking some of the fear of the unknown out of the whole experience. -She stayed with me through 17 consecutive hours of the labour -Early on, helping me with pain management, massaging me, helping me reposition myself, drawing a bath for me, photographing the labour experience. -Post-epidural (which was in place for 3 of the 17 hours she was with me), she helped a shaky-legged me (walking-epidural) to the bathroom, she would fetch food and water for my partner so he didn't have to leave my side, she'd report to family with updates, she kept me company and continued easing my mind with some nerves surrounding pushing and really finally meeting the babes! -She took pictures throughout us pushing, helped to hold baby #1 (twins) while the second was born. -She stayed to ensure we were settled and helped us keep an intimate and private environment for ourselves until we were ready to greet the pouring-in of family members. -She stayed with us at the hospital until we were sure breastfeeding would go well. -She provided us with a few visits following the birth, brought little gifts for our boys, offered to make a meal or two, brought us a beautiful birth slide show with all of the photographs she took.... AMAZING!
The plain and simple of it is...
There is so much more to having a baby than pushing, and likewise, there is so much more to a doula than someone to help you push! Look at the grander scale, and recognize how enriched your whole experience can become with the extra assistance.