Objective:

We examined differences in rates of severe maternal morbidity and mortality (SMMM) among Medicaid-funded compared with privately insured hospital births through specific additive and intersectional risk by rural or urban geography, race and ethnicity, and clinical factors.

Methods:

We used maternal discharge records from childbirth hospitalizations in the Health care Cost and Utilization Project’s National Inpatient Sample from 2007 to 2015. We calculated predicted probabilities using weighted multivariable logistic regressions to estimate adjusted rates of SMMM, examining differences in rates by payer, rurality, race and ethnicity, and clinical factors. To assess the presence and extent of additive risk by payer, with other risk factors, on rates of SMMM, we estimated the proportion of the combined effect that was due to the interaction.

Results:

In this analysis of 6,357,796 hospitalizations for childbirth, 2,932,234 were Medicaid funded and 3,425,562 were privately insured. Controlling for sociodemographic and clinical factors, the highest rate of SMMM (224.9 per 10,000 births) occurred among rural Indigenous Medicaid-funded births. Medicaid-funded births among Black rural and urban residents, and among Hispanic urban residents, also experienced elevated rates and significant additive interaction. Thirty-two percent (Bonferroni-adjusted 95% confidence interval, 19%-45%) of SMMM cases among patients with chronic heart disease were due to payer interaction, and 19% (Bonferroni-adjusted 95% confidence interval, 17%-22%) among those with cesarean birth were due to the interaction.

Conclusions:

Heightened rates of SMMM among Medicaid-funded births indicate an opportunity for tailored state and federal policy responses to address the particular maternal health challenges faced by Medicaid beneficiaries, including Black, Indigenous, and rural residents.