The use of a doula as a support person during labor can be quite helpful. Their role is to provide emotional support and comfort for the laboring patient, which they can do quite well. Doulas have limited medical training, and they are obligated to inform you that they are not medical care providers. Most doulas have been certified by an organization called DONA (Doulas of North America).

Please see the DONA website for more information:

We have worked with many different doulas and overall have found their assistance encouraging and positive.
Unfortunately, there are some doulas that have a negative attitude toward traditional medical care, hospitals and doctors. Although childbirth is a natural process, our position is that it is best done in a hospital due to the occasional serious and unexpected problems that can arise. When this occurs, a doula that tends to distrust hospital personnel can sometimes interfere with the delivery of proper medical care, and this will not be allowed.