Why do teens get pregnant ?

same reason anyone gets pregnant, they done got nutted in 

They think they have all the answers and don't know what they are doing.

They have no adult guides or supervisions that makes them want to have a bright future.

They think they are in love and that will conquer all.

They don't THINK at all.

Life is more than a few contractions of your crotch muscles.

There are a billion reasons. The biggest components tend to be lack of parental involvement and, statistically speaking, abstinence-only sex ed programs or lack of sex ed programs. 

Actually, sex ed programs are pretty ridiculous in some places. The feds fund certain types of programs, but the states set their own guidelines and individual districts/ schools set additional guidelines. In some places, there aren't even requirements that the course cover medically-accurate information or even discuss birth control. 

The whole thing is very outdated, built on a model which assumes that, if we tell teens not to have sex, they won't. Well, duh. That doesn't work. What does work is teaching them medically-accurate info about how their bodies work and giving them the information they need to make smarter decisions. However, in many areas, parents get into an uproar over their kids learning about contraception, and so programs only go into action if they're based around abstinence and don't cover safe sex.

Dr. Drew Pinsky was behind the TV show Teen Mom. He did a really popular radio show before that. I think his intentions were mostly pure. At least back then. He really was all about education and teaching people why they did the things they did and how to overcome their challenges. Something shifted when he moved away from the radio show. He still seemed to want to help, but he also got more into the entertainment value of things. There were times he acted in a way that really was not clinically appropriate... it's hard to explain, but some of what he did, especially when we look at how he handled Brittney Spears, is indicative of that. He built up interest in himself by talking about her mental health. He sensationalized it further. He shouldn't have been discussing her, especially because she met with him in a professional capacity. That was very hard to see. It seeps into a bit of Teen Mom too. He may well have started the project hoping to shed light on the hardships teem moms endure, but it really became all about entertainment. Love Line (the radio show) stood for itself, I think. It wasn't about capitalizing on the hardships of others, but about helping the people who called and teaching the audience. At least, that's what I remember of it in the pre-Teen Mom days. Dr. Drew didn't address Teen Mom and future projects through the same lens. Later projects didn't honor the people involved to the same degree. Ergo, it is my personal opinion that the Teen Mom you might watch today is not the same show that launched. I don't want to knock Dr. Drew too much because I think his earliest works did a lot of good for many people, but he took his stardom and career in a direction I don't agree with. 

You asked this same question last week.

I'm curious as to why you are asking the same question again - in exactly the same wording.

We Muggers responded with a wide range of answers, all of which were correct because there are many reasons why teenagers fall pregnant.

If our answers could not satisfy your need, what is it that you really want to know?

When I was a teen I was very sexually active and I never got pregnant. 
And believe it wasn't from lack of total commitment to what I was doing.