Republican presidential candidate Newt Gingrich acknowledged on Thursday that his support for a "fetal personhood" constitutional amendment would make some forms of birth control illegal.

Earlier in the week, the candidate had signed a pledge (PDF) from the group Personhood USA that declared he would "support a human life amendment to the Constitution, and endorse legislation to make clear the 14th Amendment protections apply to unborn children."

At a campaign event in Fort Dodge, Iowa Thursday, a young woman asked Gingrich what this meant for birth control.

"I'm just a little concerned because I personally use birth control," the woman explained. "And some forms of birth control would be outlawed if those personhood laws became the law of the land. So, do you support birth control, all forms of birth control?"

"Any kind of pre-conception birth control would be legal," Gingrich replied. "But I think post-conception birth control would be a form of abortion."

"So, you don't support that?" the woman wondered.

"No, I don't support abortion," Gingrich said.

"Or birth control?" the woman pressed.

"I said pre-conception birth control is perfectly appropriate," Gingrich insisted. "And there's lots of forms of pre-conception birth control."

The New York Times determined that a similar plan in Mississippi to declare a fertilized egg a legal person, also promoted by Personhood USA, would have banned some forms of birth control like IUDs and morning-after pills.

Personhood amendments have failed in Mississippi and every other state where they have been on the ballot.

Watch this video from CNN, broadcast Dec. 15, 2011.

Photo: Flickr/Gage Skidmore