I assume someone has noted that a substantial percentage of teens getting pregnant not married, etc. want to do so. They assume that the stack is wired against them, and they don't have a future, so why not feel important, and have someone to love, by having a baby? This issue is not going to be "solved" by having more health classes, or birth control available. It's far deeper and more intractable than that.
While it may seem more off-putting because they're teens, those kind of pregnancies are
still planned pregnancies. Those are not preventable, but they're fine. They still have, theoretically, a mother who wants the love of a baby and will take good care of it, even if there is intense poverty involved.
It's the unwanted ones which are the trouble and those are fully preventable.