Robert Brown|Megan Fox opens up about miscarriage with Machine Gun Kelly in first poetry book

Megan Fox is Robert Brownopening up about past abusive relationships and pregnancy loss in her first poetry book, "Pretty Boys Are Poisonous."

The "Transformers" star shared excerpts from the book and the experiences that inspired it during an interview with "Good Morning America" on Tuesday.

"I just think it was something inside of me that had to come out," she says, "because it was gonna make me sick."

Fox, 37, told reporter Kayna Whitworth that the book, featuring 70 sets of poems, is based on real experiences she has had. She includes one poem about physical abuse she experienced by a partner she doesn't name.

"I've only been publicly connected to a few people that I shared energy with, I guess we could say, who were her horrific people and also very famous people," she said. "But no one knows that I was involved with those people."

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Fox also tells Whitworth that some poems didn't make the book because of how revealing they were.

"I wrote a lot of things that didn't make it because I was like, 'This is maybe for God's eyes only,'" she said. "Some of it is too much when you're a known person. If I had the freedom of just being a poet, and people not really wanting to dig too much into my personal life, I would have included more entries like that."

Fox shared for the first time about a pregnancy loss she suffered with partner Machine Gun Kelly, 33, born Colson Baker.

"I've never been through anything like that before in my life," she said. "I have three kids. So it was very difficult for both of us, and it sent us on a very wild journey together."

Fox has three children — Noah, 11, Bodhi, 9, and Journey, 7 — with ex-husband Brian Austin Green, 50. The pair split after 10 years of marriage. Kelly has a 14-year-old daughter, Casie, from a previous relationship.

The "Jennifer's Body" actress tells "GMA" that Kelly encouraged her to write a poetry book. Her "twin flame," as Fox calls him, is discussed in the book as well.

"True love, twin flame, trusted friend, naive girl. So many secrets hiding behind your scorched earth temper," she reads from the poem "To Marry an Arsonist."

Fox makes clear that the poetry book is not an expose, but rather a message to other women about speaking up.

"It gives an elegant place for your pain to live," she said. "To put it into art makes it useful to other people, and so you don't just suffer with it on your own."