Urban-rural differences in pregnancy-related deaths, United States, 2011–2016

Abstract

The US pregnancy-related mortality ratio has not improved over the past decade and includes striking disparities by race and ethnicity and by state. Understanding differences in pregnancy-related mortality across and within urban and rural areas can guide the development of interventions for preventing future pregnancy-related deaths. We sought to compare pregnancy-related mortality across and within urban and rural counties by race and ethnicity and age. We conducted a descriptive analysis of 3747 pregnancy-related deaths during 2011-2016 (the most recent available data) with available zone improvement plan code or county data in the Pregnancy Mortality Surveillance System, among Hispanic and non-Hispanic White, Black, American Indian or Alaska Native, and Asian or Pacific Islander women aged 15 to 44 years. We aggregated data by US county and grouped counties per the National Center for Health Statistics Urban-Rural Classification Scheme for Counties. We used R statistical software, epitools, to calculate the pregnancy-related mortality ratio (number of pregnancy-related deaths per 100,000 live births) for each urban-rural grouping, obtain 95% confidence intervals, and perform exact tests of ratio comparisons using the Poisson distribution. Of the total 3747 pregnancy-related deaths analyzed, 52% occurred in large metro counties, and 7% occurred in noncore (rural) counties. Large metro counties had the lowest pregnancy-related mortality ratio (14.8; 95% confidence interval, 14.2-15.5), whereas noncore counties had the highest (24.1; 95% confidence interval, 21.4-27.1), including race and ethnicity and age groups. Pregnancy-related mortality ratio age disparities increased with rurality. Women aged 25 to 34 years and 35 to 44 years living in noncore counties had pregnancy-related mortality ratios 1.5 and 3 times higher, respectively, than women of the same age groups in large metro counties. Within each urban-rural category, pregnancy-related mortality ratios were higher among non-Hispanic Black women than non-Hispanic White women. Non-Hispanic American Indian or Alaska Native pregnancy-related mortality ratios in small metro, micropolitan, and noncore counties were 2 to 3 times that of non-Hispanic White women in the same areas. Although more than half of pregnancy-related deaths occurred in large metro counties, the pregnancy-related mortality ratio rose with increasing rurality. Disparities existed in urban-rural categories, including by age group and race and ethnicity. Geographic location is an important context for initiatives to prevent future deaths and eliminate disparities. Further research is needed to better understand reasons for the observed urban-rural differences and to guide a multifactorial response to reduce pregnancy-related deaths.