Romney was responding to comments Democratic strategist Hilary Rosen made Wednesday on CNN, the Los Angeles Times reported. Rosen suggested Romney has little knowledge of what working mothers go through because she has never "worked a day in her life."
"I made a choice to stay home and raise five boys," Ann Romney said on Twitter under the handle @AnnDRomney. "Believe me, it was hard work."
The campaign said the handle is indeed an official one.
Polls suggest women are far more likely to support President Barack Obama than men this year.
Jim Messina, Obama's campaign manager, and other Obama campaign advisers criticized Rosen, saying families are "off limits." Rosen does not have an official role in the Obama campaign.