Richie told "Access Hollywood" it "wasn't an overnight decision" but she wanted to "heal any wounds before I become a mother myself."
"When I found out that I was pregnant, there was just something inside of me that felt a responsibility to mend any issues that I've had with my parents in the past, because, listen, I have put them through a lot," Richie said.
Richie also said her adoptive father, singer Lionel Richie, is thrilled about becoming a grandfather to her first child with boyfriend Joel Madden.
"It's all he talks about, actually. Of course, a father's first reaction, he was quiet and didn't really know what to think and I just said, 'OK, so that's the news, so call me tomorrow,' because I like to give him a day whenever I give him news. He called me the next day and he was so excited and now he just doesn't stop. He has all these names that he's ready for the baby to call him, in substitute of 'grandpa,' because he doesn't like 'grandpa.'"