The governor says Amendment 48, the so-called "personhood" amendment, on the Nov. 4 statewide ballot, could endanger the health of women in Colorado, the Denver Post reported Wednesday.

"I believe the amendment goes too far," Ritter said. "It threatens medical care, and it would create a legal nightmare in our state."

"In spite of the fact that I'm pro-life, I can look at this and really find reasons I think it is just such an extreme position to take," Ritter said.

Observers say Ritter's opposition raises questions about his anti-abortion bona fides.

"He's in a dicey spot with Amendment 48," said Tom Hooyman, a professor of medical ethics at Regis University. "It's clearly a pro-life amendment. For him to come out and oppose it, you have to say, 'What does it mean to be a pro-life Catholic?' "