"Gov. Romney supports the Blunt Bill because he believes in a conscience exemption in health care for religious institutions and people of faith,” Romney spokeswoman Andrea Saul said in a statement.
The amendment, set for a vote in the Senate this week, would allow employers to opt out of healthcare mandates that violate their religious or moral beliefs.
The DNC, previewing planned events Thursday in Ohio, will push hard to associate Romney with the type of social conservatism usually associated with his GOP rival Rick Santorum.
"The Affordable Care Act gives millions of women control over their own healthcare," reads the video. "Mitt Romney would take it away."
Ohio votes next week, on Super Tuesday.