Hoping to preserve a rare victory, women's groups are keeping close watch on upcoming House-Senate negotiations over legislation requiring insurance coverage of contraceptives for more than 1 million women.

The bill would require federal employee health insurance plans to cover the five forms of prescription birth control: the pill, diaphragms, intra-uterine devices, Norplant and Depo-Provera. Insurance plans sponsored by the Roman Catholic Church would be exempt.Backers of the provision hope federal coverage will be a step toward much broader legislation that would require all health plans to offer women coverage for contraceptives.

The insurance industry says coverage for contraceptives is available but unpopular with employers that must pay for it. Business groups contend that government mandates will increase the cost of health care across the board.

But women's groups, noting the shift toward prevention in health care, argue that coverage of contraceptives can help insurers avoid the higher costs of unwanted pregnancies.