I'm a doula as well, and I find most of the questions that you find online aren't really the best to find the "right" doula for you.
Here are my questions that I'd ask/like to be asked:
Describe your best doula experience. How did the birth go, what happened, how did the mom cope?
(This gives you a good idea as to what the doula really considers the "gold standard" of birth. Often doulas will just agree that whatever you want is all good, but they may not actually mean that.
What was the hardest birth you ever attended?
How many births have you attended and where do you attend the majority of births?
What is your most used tool at a birth? (It could be, massage, birth ball, her voice, aromatherapy, etc) whatever it is, make sure it seems important to you.
What happens in case you are not available to attend my birth? Who will be there instead?
What experience do you have with breastfeeding?
What personality traits do you have that make you a great doula?
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