Being six months pregnant during the making of Traffic didn't pose any problems for star Catherine Zeta-Jones. When it comes to making babies, the newlywed wife of actor Michael Douglas — who also appears in the Steven Soderbergh-directed film — says she was "born to breed."

"I had a very easy pregnancy," the actress tells TV Guide Online. "If I didn't feel so good, I would never have put myself and my baby at risk just for a movie — as much as I wanted to do this."

Zeta-Jones, whose Traffic duties netted her a Golden Globe nomination for best supporting actress, didn't experience one single bout of morning sickness during the entire shoot. In fact, she says, being pregnant actually helped her prepare for her role as a protective mother caught in the world of drug trafficking.

"There is this profound instinct that kicks in when you're carrying a child," says Zeta-Jones, who gave birth to son Dylan four months ago. "You have this instinct to protect and preserve and nurture this little human being that is your life, and is part of you and is so dependent on you. I couldn't believe this instinct that just kicked in from nowhere. It sideswiped me, and I used that."

It should come as little surprise then that the gung-ho baby machine is looking forward to expanding her family. "I had so much energy when I was pregnant," she marvels. "Really, up until the day I gave birth, I had the hormone that kicks in. Michael said to me so many times, 'Just get off your feet, have a cup of tea, watch daytime TV like everyone else and have lots of chocolate.' I was on a ladder, writing lists, organizing, getting clothes for when the baby would be one-year old — it was just really crazy!"