research is also needed to identify the causes of the large proportion of developmental disabilities with unknown origins and to find the basis for the excess of developmental disabilities observed among the socioeconomically disadvantaged.

In summary, the goal of these efforts is to prevent developmental disabilities and reduce the incidence and severity of secondary conditions. To reach this goal, effective preventive measures must be implemented. The scientific base of known preventive interventions should be expanded by further evaluating promising strategies and by identifying the preventable risk factors that may underlie disabilities of unknown origin and etiology.

Comprehensive, coordinated services in health care, education, environmental control, and peer support are encouraged at the federal, state, and community levels. In addition, efforts to monitor prevention programs and establish uniform definitions and data collection methods will advance program coordination and accountability.

The financing of health care and preventive interventions in the United States is complex, involving contributions from public programs, private insurers, and families (Table 4-6). This complicated strategy makes it increasingly difficult for all citizens to have equal access to health care and preventive services.

Inadequate insurance coverage is the single greatest barrier to equal access to health care, according to a Robert Wood Johnson Foundation study (1987). Lack of insurance coverage for preventive care services for women of childbearing age is a particular problem. More than 14 million women in this category (ages 15 to 44) do not have prenatal or other maternity coverage, 9 million are completely uninsured, and 5 million have private insurance coverage that excludes maternity care (Alan Guttmacher Institute, 1987).

The cost of immunizations and other pediatric preventive care is a strong disincentive for uninsured families who might otherwise obtain these services. Nineteen percent of children under 18 (10.6 million) had no insurance coverage in 1986 (Chollet, 1988). Thirty-three percent of all uninsured children had family incomes below the poverty level. In 1987, children under age 21 represented 52 percent of all Medicaid recipients and only 19 percent of expenditures. The average payment per child was $742, compared with $3,362 for adults (U.S. Health Resources and Services Administration, 1989).