Will my girlfriend get pregnant if she takes birth control?

Yes: The chances of getting pregnant on birth control pills is roughly 4/100. So if 100 couples use birth control pills correctly.....4 of them will get pregnant at the end of a year.

Options vary: Birth control methods vary in effectiveness==see the chart http://www.Contraceptivetechnology.Org/table.Html sterilization (male and female), iuds, and implants are the most effective. Consistent use of a method is important for it to be as effective as it can be.