From the Huffington Post:

Jillian Michaels: I won't ruin my body with pregnancy

'Biggest Loser' trainer Jillian Michaels has a hard little body and she plans to keep it that way. Michaels, 36, tells Women's Health she is unwilling to become pregnant because of the way it would change her body.

"I'm going to adopt. I can't handle doing that to my body," she told
the magazine. "Also, when you rescue something, it's like rescuing a
part of yourself."

Read the article here.