the ability to accurately estimate the size of the migrant and seasonal farmworker population.

The variations and imprecision in population estimates make it extremely difficult to calculate vital statistic rates. A number of sources quote a life expectancy of 49 years, as compared with the national average of 75 years, for migrant farmworkers, and an infant mortality rate that is 125 percent above the national average (National Migrant Resources Program and the Migrant Clinicians Network, 1990). However, literature searches commissioned by the Department of Health and Human Services in 1984, the Farmworker Justice Fund in 1985 and 1988, and one performed by a migrant health physician in 1990 revealed no published studies that included specific mortality or survival data (Rust, 1990). A literature search performed for this paper and personal communications with personnel from the Office of Migrant Health also failed to discover data on life expectancy, age-specific mortality, or crude death rates.

Recent information about perinatal outcomes is equally hard to obtain. Infant mortality and low birthweight rates of women using migrant health centers (see the later discussion) have not been calculated. Most studies of birth outcomes are at least 15 years old. In 1978, a study that relied on the mother's recall questioned 132 women in Wisconsin (Slesinger and Christensen, 1986). The authors reported an infant mortality rate of 29 per 1,000 and a mortality rate of 46 per 1,000 children up to the age of 5. Infant mortality among Mexican American farmworkers in Colorado was reported to be 63 per 1,000 in 1971. This rate was three times the national rate for the period (Chase et al., 1971).

The Office of Migrant Health records that 500,000 migrant and seasonal farmworkers and their dependents annually use the 102 migrant health centers located in 43 states and Puerto Rico (These figures are derived from unpublished data for calendar year 1990–1991 from the Health Resources and Services Administration's Bureau of Health Care Delivery and Assistance.) These users represent approximately 17 percent of all migrant and seasonal farmworkers and their families, if one's calculations employ the Public Health Service's number of eligibles as the denominator. We cannot know how representative the users of migrant health centers may be of the total population of migrant and seasonal farmworkers; nevertheless, some information regarding their health status is available and may indicate some general trends.

In a survey of migrant health centers (with a 49 percent response rate from centers representing 54 percent of all patients served nationally), the migrant health centers identified the following as the most common conditions among their maternity and pediatric patients: malnutrition, anemia, hypertension, gestational diabetes, and infection among the pregnant women. For children, the most commonly reported conditions were lack of