By Lauren Mann of the National Campaign to Prevent Teen and Unplanned Pregnancy

There are all sorts of reasons why the girls on this season of "16 and Pregnant" weren't on birth control. A few examples: They didn't think about it, they were afraid to talk about it with their parents, they thought it made you gain weight and they just didn't think pregnancy would happen to them. But all of them have something in common: they got pregnant before they were ready to have a baby.

The only 100 percent effective way to prevent an unplanned pregnancy is to not have sex at all. But if you are going to have sex, you need to make sure to use an effective method of birth control correctly, every single time you have sex.

Watch the girls use their experiences to help others make better birth control choices, and then check out Bedsider.org to find the method that's right for you.