The Femme Fatale performer is mother to Sean Preston, 6, and Jayden James, 5, from her marriage to Kevin Federline. She told Harper's Bazaar that her perspective on work had changed as a result of motherhood.
She also explained to the magazine, which featured a heavily-pregnant Spears on the cover of their August 2006 edition, that she also has more concerns over her career than she did prior to her sons' arrivals.
"I think things through a little bit more, and I worry a lot. I'm more straightforward, and I speak up more than I did before," Spears said.
"When I was younger, I wouldn't speak up as much, but now that I'm a mum, things have changed."
She also said that she would be happy to have more children "if the timing was right" and that she would be happy for her kids to go into the entertainment business.
"If they have a love and passion for the arts and that's what they want to do, then so be it," she said. "They are both little actors and so charismatic, I wouldn't be surprised at all."
The 29-year-old, who is preparing to launch her Femme Fatale tour, has reportedly demanded a "healthy" environment for the roadshow.