Original Research| Volume 5, ISSUE 5, 100917, May 2023

Racial/ethnic disparities in costs, length of stay, and severity of severe maternal morbidity


      In contrast to other high-resource countries, the United States has experienced increases in the rates of severe maternal morbidity. In addition, the United States has pronounced racial and ethnic disparities in severe maternal morbidity, especially for non-Hispanic Black people, who have twice the rate as non-Hispanic White people.


      This study aimed to examine whether the racial and ethnic disparities in severe maternal morbidity extended beyond the rates of these complications to include disparities in maternal costs and lengths of stay, which could indicate differences in the case severity.


      This study used California's linkage of birth certificates to inpatient maternal and infant discharge data for 2009 to 2011. Of the 1.5 million linked records, 250,000 were excluded because of incomplete data, for a final sample of 1,262,862. Cost-to-charge ratios were used to estimate costs from charges (including readmissions) after adjusting for inflation to December 2017. Mean diagnosis-related group–specific reimbursement was used to estimate physician payments. We used the Centers for Disease Control and Prevention definition of severe maternal morbidity, including readmissions up to 42 days after delivery. Adjusted Poisson regression models estimated the differential risk of severe maternal morbidity for each racial or ethnic group, compared with the non-Hispanic White group. Generalized linear models estimated the associations of race and ethnicity with costs and length of stay.


      Asian or Pacific Islander, Non-Hispanic Black, Hispanic, and other race or ethnicity patients all had higher rates of severe maternal morbidity than non-Hispanic White patients. The largest disparity was between non-Hispanic White and non-Hispanic Black patients, with unadjusted overall rates of severe maternal morbidity of 1.34% and 2.62%, respectively (adjusted risk ratio, 1.61; P<.001). Among patients with severe maternal morbidity, the adjusted regression estimates showed that non-Hispanic Black patients had 23% (P<.001) higher costs (marginal effect of $5023) and 24% (P<.001) longer hospital stays (marginal effect of 1.4 days) than non-Hispanic White patients. These effects changed when cases, such as cases where a blood transfusion was the only indication of severe maternal morbidity, were excluded, with 29% higher costs (P<.001) and 15% longer length of stay (P<.001). For other racial and ethnic groups, the increases in costs and length of stay were smaller than those observed for non-Hispanic Black patients, and many were not significantly different from non-Hispanic White patients. Hispanic patients had higher rates of severe maternal morbidity than non-Hispanic White patients; however, Hispanic patients had significantly lower costs and length of stay than non-Hispanic White patients.


      There were racial and ethnic differences in the costs and length of stay among patients with severe maternal morbidity across the groupings that we examined. The differences were especially large for non-Hispanic Black patients compared with non-Hispanic White patients. Non-Hispanic Black patients experienced twice the rate of severe maternal morbidity; in addition, the higher relative costs and longer lengths of stay for non-Hispanic Black patients with severe maternal morbidity support greater case severity in that population. These findings suggest that efforts to address racial and ethnic inequities in maternal health need to consider differences in case severity in addition to the differences in the rates of severe maternal morbidity and that these differences in case severity merit additional investigation.

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