Stillbirth risk with social class and deprivation: no evidence for increasing inequality.

The objective of this study was to determine whether inequality in stillbirth risk between social strata has changed over time. Subjects were all 288,869 births in Cumbria, northwest England, 1950-1993 and all 8,039,269 births in England and Wales, 1981-1992. Social class of Cumbrian babies was ascertained from birth registrations. Community deprivation scores were calculated from census data for (i) enumeration districts in Cumbria and (ii) county districts in England and Wales. The relative index of inequality was used to measure inequality of stillbirth risk between social strata. Results indicate inequality in stillbirth risk in Cumbria has fallen significantly since 1966 (P< or =0.02) and was not evident in more recent time periods. In England and Wales, there was significant inequality in stillbirth risk in all time periods and no evidence that this has changed over time. Inequality in stillbirth risk has not increased and in some areas has attenuated in recent years.