Mrs. Obama, championing the health care effort at the White House while her husband travels through Asia, said women are among those struggling the most under the current system and would benefit from health care overhaul.
She said there's been "a lot of misinformation" and she wanted to be clear that the legislation in Congress would make Medicare more stable by eliminating wasteful subsidies to private insurance and cracking down on fraud.
"My husband believes that Medicare is a sacred part of America's social safety net and it's a safety net that he will protect - he will protect - with health insurance reform," she said.
To pay for part of the overhaul, the House bill would cut more than $400 billion from Medicare and Medicaid. Democrats argue that the cuts can be made, especially to the Medicare Advantage program that lets private insurers contract with Medicare to provide coverage. Republicans countered that seniors would be hurt by the cuts, and Congress' nonpartisan budget analyst told a Senate panel that benefits could indeed be reduced.
Mrs. Obama targeted two important groups in her meeting. Women, like the public overall, are generally split on the health care legislation. And polls have shown people age 65 and older have also had the most negative views about President Barack Obama's attempt to overhaul health care.
Mrs. Obama, addressing women and seniors advocates in the audience such as the president of the seniors' lobby AARP, said women face special challenges because they often make less money and have to pay higher premiums. She said Obama's health care proposals will make seniors' prescription drugs affordable, provide stability for those who have insurance and make coverage affordable for Americans who don't have it.
"That's what reform will mean for older women, for seniors and for all Americans," she said.
Before Mrs. Obama spoke, three women invited by the White House explained their health insurance problems and difficulties in paying for coverage.