Dear friend

What I feel is that as a parents one can prevent teen pregnancy by getting involved in their teen's lives. Talks to your teen everyday and tell them that you are there for them. Get interested in what your teen is interested in and if they have no interests, help them find some. Be active as a family and show your unconditional love.
The more you are involved with your teen, the more you will be able to keep a track upon there action. You should also try to have direct communication with your teens on the issues like teen pregnancy and the issues related to it.