I've a friend who recently became an OB, and she thinks doulas are great. The hospital she did her residency at was in the inner city, and she said that the volunteer doulas that worked there made a tremendous difference for the mothers who used them.
(She also thinks epidurals are wonderful, and hasn't seen many natural births, but --- I have hopes that she will come 'round as she becomes more established in her career; she's always been very vocal about how strong women are, and I think as she sees more clients who do NCB and so on, she'll see why it's not as awful as med school indoctrinated her to believe).
I really do think that the "hurry hurry, I'd like to get some sleep tonight!" approach from some OBs (in terms of introducing interventions to speed things up) is more difficult for OBs (or MWs) to do if the mother is educated/informed, and/or if she has a good support person in place (partner, doula, whoever). And I know my friend the OB doesn't think there's any difference in pit contractions vs. physiological ones....
I shudder when I hear about OBs like this ... mine is awesome, he has a real midwife-like approach to birth and I know he has enjoyed both of my births with him. But I think he's an exception .....

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