Viagra: The Trend: In the past few weeks, several major plans, led by Kaiser Permanente, have announced that they will not pay for Viagra prescriptions. Kaiser, with 8 million members, estimated that it would cost $100 million per year to treat its members' erectile dysfunction, more than the $59 million it spends on all anti-viral drugs. An exception: Last week, the federal government ordered states to pay for Viagra for Medicaid patients when medically necessary, over intense opposition from several Governors concerned about the costs.

Heart Attacks: The Trend: To protect against a second heart attack, most major health plans cover the cost of beta-blockers, medication that helps to regulate blood pressure and protect the heart. On average, more than 90% of heart attack patients in top health plans across the U.S. are covered for this preferred treatment. An Exception: Big managed-care plans in the South Central U.S. (Ala., Ark., Ky., La., Miss., Okla., Tenn., Texas) seem to be resisting beta-blockers: fewer than 20% of their patients are covered. If you live there and have a family history of heart disease, check your coverage.

Breast Cancer: The Trend: Even though bone-marrow transplants may represent the only chance for survival for some breast-cancer patients, most HMOs refuse to cover these expensive treatments because the federal government still classifies them as experimental. An Exception: The Wellness Plan of Detroit, a more progressive plan that represents 150,000 people in southeastern Michigan, covers the implants not only for breast cancer, but also for ovarian and testicular cancers, Hodgkin's Disease and aplastic anemia.

Infertility: The Trend: During the past year, many large companies that did not previously cover this treatment for would-be parents have been telling their health plans to add the coverage. Some 22% of large employers now cover this treatment under their HMO plans, up from 19% in 1996. An Exception: During the same period, a number of small companies, concerned about the costs of this treatment, have been instructing their health plans to eliminate this coverage for their employees. Only 13% of HMOs serving small companies now offer it, down from 20% in 1996.

Mental Health Care: The Trend: Thanks to the 1996 Mental Health Policy Act, employers across the country are improving mental health coverage. For example, they are eliminating caps they had placed on mental health care for their employees, which often resulted in patients being denied care once they'd used up their allotment. An Exception: Tennessee's TennCare Partners plan, a mental health care system run by the state, is one of the stingier plans. It offers virtually no preventive mental health care and bounces patients from mental hospitals after a few days. Some parents have been told that in order to get treatment for their mentally-ill children they must put them in state custody. A state commission is investigating TennCare.