Nearly 15 million American women of childbearing age have no private or government health insurance covering maternity, and 555,000 each year give birth without any health insurance protection, according to a report released yesterday by The Alan Guttmacher Institute.

"What should be a blessed event too often can be a financial nightmare for new parents in America," said Jeannie Rosoff, president of the nonprofit research organization.

The report said lack of insurance leaves more than 1.3 million women with insufficient prenatal care, and "although virtually all deliveries take place in hospitals, many women arrive with no records and are treated by doctors who do not know their medical history."

As a result, "twice as many women who do not have adequate prenatal care have premature births and low-birthweight babies, significant factors in complications" and subsequent deaths.

Since the typical costs of having a baby are about $4,300, the report said, families lacking insurance are often left with whopping bills and hospitals left with huge losses. The report said that about $2 billion of $7.4 billion in annual hospital losses for unpaid care "is accounted for by unpaid bills in maternity care."

The report, which defined childbearing age as between 15 and 44, said two-thirds of the 15 million women without coverage don't have health insurance policies, although some obtain partial coverage from Medicaid once they are pregnant. The other third has some health insurance but it doesn't cover maternity.

"The percentage of women getting insufficient prenatal care is highest among the unmarried, teen-agers, blacks, Hispanics, the least educated and the poor," the report said.

The report cited several examples of the impact of lack of insurance.

In Rhode Island, five obstetricians were the only prenatal care givers in Newport, Middletown and Portsmouth. They said they had to discontinue prenatal services to Medicaid patients because Medicaid only paid $350 for maternity care, not enough to cover even their overhead costs of $400, let alone match the $1,300 paid by most private patients.

In Hyattsville, according to a Jan. 20 account in The Washington Post Health section describing a Senate committee hearing, a couple identified as John and Michelle Muir had health insurance through their employers, the report said, but ended up about $430,000 short on bills when their health insurance didn't cover the bulk of costs for a child born prematurely. Efforts to reach the couple yesterday were unsuccessful.

According to federal figures, about 35 million to 37 million people in the United States lack any insurance -- private, Medicaid, or any others. About two-thirds of them are in families of employes whose firms do not provide health insurance, usually smaller, less affluent companies.

Although most people believe Medicaid provides health benefits to any low-income person who needs it, the report notes that there are huge gaps in coverage. In the nation's younger population, it covers only the blind and disabled and low-income families with dependent children, although some women are eligible once they are pregnant, and the income cutoff varies from state to state. In some states, the income cutoff is only half the poverty line.

The report said possible solutions to the absence of coverage might be to require coverage for maternity care by all private policies, to force private plans to waive waiting periods and restrictions on coverage, to open the Medicaid system to those who cannot purchase private insurance, and to reduce various administrative obstacles.