Are you aware that in Alaska our Public Health centers provided birth control services at no cost to low cost for teenagers ? 
I was with two of my former foster daughters while they got implants in thier arms. Within six months they had them removed and had gotten pregnant again. While they may be exceptions, most teenagers or "poor women" do have the means to get birth control. Medicaid covers prescriptions for birth control in Alaska but not for abortions. 
Some school based health programs do the same. 
For most teens wanting birth control there is help available. Health classes often provide students with the resources available. 
For the teenagers who have emotional or religious reasons for not getting birth control, they are high risk for pregnancy.
You might check with your public health center, maybe they have quit giving birth control pills and condoms away but most still do. As for IUD's and the arm implants, a nurse practitioner trained to do it can provide the service.