The bill, signed into law by Obama in 2009, expanded workers’ ability to sue over equal-pay discrimination claims.

“We'll get back to you on that,” a Romney adviser answered. Romney's campaign later clarified that "of course" the candidate supported pay equality for women.

The war over female voters has intensified in recent weeks after a Gallup poll showed a wide gender gap in support for Romney vs. President Obama in 12 swing states, with Obama leading. Romney made an aggressive bid for women this week, seeking to convince them Obama's policies have failed to help find them jobs.

Female House Republicans who support Romney jumped to defend his record on women, with the campaign sending out counter-attacks on President Obama's policy failures for women all Wednesday afternoon. But no opposing hashtag popped up on Twitter. Romney tweeted using the hashtag #ObamaLegacy and Rep. Mary Bono Mack (Calif.) used #ObamaIsntWorking.

This post was updated at 4:18 p.m.