The film, which was directed by the singer, airs on the US cable network on February 16.
The teaser shows Beyoncé discussing the pressures of her career, saying: "How do I stay current? How do I stay soulful? I felt like I had been so commercially successful, it wasn't enough.
"It's something really stressful about having to keep up with that. You can't express yourself. You can't grow. It is the battle of my life, so I set a goal. And my goal was independence."
Viewers also get to see the moment the 'Single Ladies' star discovered she was pregnant, and her efforts to hide her bump during the early stages.
"People see celebrities, they have money and fame, but I'm a human being," Beyoncé adds. "I cry, I get scared, I get nervous just like everyone else."
Beyoncé recently revealed that she has been working with Justin Timberlake, Timbaland, Pharrell Williams and The-Dream on her new album, which is due out sometime this year.