CHICAGO - Most working-age women in the United States have too little health coverage, and often forgo needed care because of cost, U.S. researchers said on Monday.

They found that seven out of 10 women have no insurance, not enough insurance or are in debt because of medical bills.

"More families are making difficult choices between needed health care, making payments on mortgages or credit card debt and purchasing basic necessities," said Karen Davis, president of the Commonwealth Fund, a private health policy group that conducted the research.

President Barack Obama renewed his push for healthcare reform on Monday at a joint appearance with the American Medical Association, America's Health Insurance Plans and the American Hospital Association. The trade groups have pledged to reduce the annual growth of health spending by 1.5 percentage points, which they say will save $2 trillion over 10 years.

Members of Congress who will shepherd healthcare reform through the process have promised to have a bill by the end of the year.

The Commonwealth Fund team said rising health costs hit women harder because they have lower average incomes and spend more on healthcare than men, and because they use the health system more often than men.

The report was based on telephone surveys of 2,600 adults aged 19 to 64 between June and October 2007.

It found that 70 percent, or 63.8 million, working-age women are uninsured, underinsured, have medical bill problems or medical debt, or did not access needed care because of cost. That compared with 59 percent, or 51.9 million, working-age men.

The team also found that 52 percent of women were more likely to leave a prescription unfilled, skip a recommended medical test or treatment, or fail to seek needed medical care. That compared with just 39 percent of men.

And they found that 45 percent of women had medical debt or reported problems paying medical bills, compared with 36 percent of men.

Because the study is based on a 2007 survey, the researchers said it likely underestimates the problem because it does not account for the full impact of the current economic recession and job cuts.

An estimated 46 million Americans lack health insurance.

(Reporting by Julie Steenhuysen; Editing by Maggie Fox and Eric Beech)