Monitoring perinatal mortality rates: California, 1970 to 1976.

Recent developments have emphasized the need to monitor perinatal mortality statistics by small geographic areas. A method is presented which separates county-specific perinatal mortality rates into a component reflective of socioeconomic, behavioral, and environmental variables, and a component that relates more directly to hospital-based intra- and postpartum care. Major differences in geographic variations were observed between the crude rate and the two components. An arbitrary index of the need for perinatal health services was created by combining the two components with the number of perinatal deaths in each county. Although there are some obvious limitations, the index serves as a useful guidepost for monitoring perinatal mortality on a statewide basis.