Minaj, 32, said their relationship led to her getting pregnant, which was not part of her plan at the time, reported Us magazine.
"I thought I was going to die. I was a teenager. It was the hardest thing I'd ever gone through. It (abortion) has haunted me all my life," she said.
The 'All Things Go' hitmaker, who is still affected by her past, said she did what she thought was right at the time.