Cardiovascular Severe Maternal Morbidity and Mortality at Delivery in the United States: A Population-Based Study

Cardiovascular conditions are the leading cause of maternal mortality in North America.

The purpose of this study was to examine the relationship between cardiovascular severe maternal morbidity (CSMM) and mortality during delivery hospitalization.

We performed a cohort study using the Health Care Cost and Utilization Project, Nationwide Inpatient Sample, and identified delivery hospitalizations with CSMM from 1999 to 2015. We described temporal trends in the incidence of CSMM and its associated case-fatality. Among individuals with CSMM, we evaluated the association between participant characteristics and mortality using logistic regression analyses.

Of 13,791,605 delivery hospitalizations, 11,152 were complicated by CSMM. Of those, 495 resulted in mortality. The overall incidence of CSMM was 8.09 per 10,000 delivery hospitalizations (95% CI: 7.94-8.24), increasing from 7.76 to 8.38 per 10,000 delivery hospitalizations over 15 years (P < 0.001). The overall case-fatality for CSMM was 4.44 per 100 CSMM (95% CI: 4.06-4.85), decreasing from 6.55 to 2.50 per 100 CSMM events over the study period (P = 0.035). Among participants with CSMM, Black (adjusted odds ratio [aOR]: 1.80; 95% CI: 1.39-2.32) and Hispanic (aOR: 1.44; 95% CI: 1.09-1.90) women and those with Medicaid insurance (aOR: 1.52; 95% CI: 1.22-1.88), postpartum hemorrhage (aOR: 4.06; 95% CI: 3.05-5.41), or systemic lupus erythematosus (aOR: 2.50; 95% CI: 1.31-4.78) were at increased risk of mortality.

The incidence of CSMM increased over 15 years, reflecting transformations within the obstetric population. Although it decreased during the study period, case-fatality from CSMM remained elevated. Several factors associated with mortality from CSMM were identified.