According to a new study of 320 first-time mothers published in the Jan. issue of the American Journal of Obstetrics and Gynecology, there are only minimal measurable benefits to coaching during labor: final stage pushing only lasted an average of 13 minutes less for the coached deliveries (59 min. vs 46 min.).
The women in the study all had simple pregnancies and no epidurals. Half received midwife-nurse coaching and half were told to "do what comes naturally." I would've thought "do what comes naturally" means "demand to know where the freakin' anesthesiologist is," but that's just me. They did it for science.
In the absence of any definitive benefits or conclusive harm, the decision to get a birth coach seems based on the woman's own sense of comfort--and her attachment to that $1,000 or whatever a doula costs these days.
Coaching women during childbirth has little impact [reuters, also in the Houston Chronicle, via dt reader paul]