"I was terrified to tell my parents. Terrified," she recalled. "Especially my father. They would have been disappointed in me. I would have been a failure. My father would have just gone ballistic."
Osbourne chose to terminate the pregnancy and found herself "so ill" afterward.
"I had to tell my mother because she was calling the doctor and I had to tell my mother," said the host.
However, her mother's reaction wasn't quite as dramatic as she expected.
"She basically said, 'You did this, you've got to go through this on your own and you think you're such a big girl, you do it on your own,'" remembered Osbourne. "And I was like, 'OK I get it,' but you are terrified."
After revealing the news to her mother, Osbourne said she felt "afraid and so alone" and felt that she'd brought "shame" to her family.
"I didn't think of [my mother] as, 'Oh, how can you say this to me, you're my mom,' I was just thinking, 'Oh my God, the shame I've caused this family,'" she recalled.