The 68-year-old opened up about her experience during an appearance on US chat show The Talk, in which the panel were discussing Jamie Lynn Spears, who in August became trustee of older sister Britney’s estate.
Mother-of-two Spears recently opened up about how she felt like she needed to “hide away” after discovering she was pregnant at the age of 16 and Osbourne said she could easily identify with her.
Osbourne told her co-stars that she could understand where Spears was coming from after she also fell pregnant as a teenager, explaining that she was so worried about her father going “ballistic”.
“I was pregnant at 18, I was just 18,” she explained. “I was terrified to tell my parents. Terrified.”
She continued: “Especially my father. They would have been disappointed in me. I would have been a failure.”
Osbourne shook her head as she recounted how she felt at the time, continuing: “I would have been…my father would have just gone, oh, ballistic.”
The former X Factor judge said she made the choice to have an abortion and only told her mother what had happened afterwards.
“I came home, I was so ill, I was so thick, and I had to tell my mother because she was calling the doctor, and I had to tell my mother,” she said, adding that her mother told her: “You did this. You’ve got to go through this on your own.”
The television personality was 30 when she gave birth to eldest child Aimée, who is now 37, in 1983.
She also shares daughter Kelly, 35, and son Jack, 34 with husband Ozzy Osbourne.
Her latest discussion about abortion comes shortly after the star opened up about considering suicide three years ago.
Osbourne told her story while appearing on ITV talk show Loose Women, saying: “Three years ago I had a very bad time in my life and I just thought, 'I'm going to bail I can't take it anymore. I just can't take the pressure'."
When asked by panellist Jane Moore what stopped her from taking her own life, the television personality answered: “My husband found me and took me to the hospital.”
She also spoke about an encounter she had with two girls while she was in treatment, both of whom had mothers who had taken their own lives.
“The damage that was left for them – I would never do it again,” she said.