Rural-Urban Differences in Maternal Mortality Trends in the US, 1999-2017: Accounting for the Impact of the Pregnancy Status Checkbox

Abstract

Abstract Rural-urban differences in maternal mortality ratios (MMR) in the United States have been difficult to measure in recent years due to the incremental adoption of a pregnancy status checkbox on death certificates. Using 1999-2017 mortality and birth data, we examined the impact of the pregnancy checkbox on MMRs by rural-urban residence (large urban, medium/small urban, rural), using log-binomial regression models to predict trends as if all states had adopted the checkbox as of 1999. Implementation of the checkbox resulted in an average estimated increase of 7.5 maternal deaths per 100,000 live births (95% CI: 6.3, 8.8) in large urban areas (76% increase), 11.6 (95% CI: 9.6, 13.6) in medium/small urban areas (113% increase), and 16.6 (95% CI: 12.9, 20.3) in rural areas (107% increase), compared with MMRs prior to the checkbox. Assuming all states had the checkbox as of 1999, demographic-adjusted predicted MMRs increased in rural, declined in large urban, and did not change in medium/small urban areas. However, trends and urban-rural differences were substantially attenuated when analyses were limited to direct/specific causes of maternal death, which are likely subject to less misclassification. Accurate ascertainment of maternal deaths, particularly in rural areas, is important for reducing disparities in maternal mortality.