I actually had my first teen mom a few months ago.
I would agree with the previous poster who said that it's not so much about avoidance of meds, etc., as it is about the support and nurturing. This is true. I have to also agree that teens are as individual as anyone else.This is also true.
Teens don't always have the support of family/community/peers in the situation, but often they do- again it's an individual thing, of course.
You may find you are a comforting presence for your client's family members also. For instance, my client's mom really leaned on me and I was happy to be there. I showed her that she could be there for her daughter as a major support person. It was lovely to see her do it and to see her daughter respond to it so positively.
All in all, I really loved the experience, I'd do it again.
There were frustrating aspects like: my client was really not good at keeping appointments... but there were times when there were really good reasons for that, so I just rolled with it. (Some adults have issues with that too... it's challenging, no matter what.)
Custody can be an issue. It was a major issue for my client- very tough. Lots of argument, threats, and manipulation. When this becomes a facet of the perinatal experience, it can easily become a stressor. Happy to say that the situation has since been sorted through, and so far, so good.
Based on this one experience, I'd say that being an educator to the appropriate extent, flexibility, having good humor, being respectful, using good listening skills, being consistent and accepting, offering warmth and nurturing, and knowing when to back off are all wonderful qualities that really get a work out not just in your average doula/client relationship, but may have extra value in working with teens.
My experience is limited, yes, but working with a teen was a wonderful adventure as a doula and I really value it. I learned alot about teens, about families, about doula work and about myself. Serving a teen deepened my commitment to all my future clients and to my work.