Delivery-Related Maternal Morbidity and Mortality Among Patients With Cardiac Disease.

Objective: To assess the risk of severe maternal morbidity (SMM) and mortality among pregnant patients with cardiovascular disease (CVD).

Methods: This was a retrospective cohort study of U.S. delivery hospitalizations from 2010 to 2020 using weighted population estimates from the National Inpatient Sample database. The primary objective was to evaluate the risk of SMM and maternal mortality among patients with CVD at delivery hospitalization. International Classification of Diseases, Ninth and Tenth Revision, Clinical Modification codes were used to identify delivery hospitalizations, CVD, and SMM events. Multivariable logistic regression analyses were performed to compare SMM and mortality risk among patients with CVD and those without CVD. Given the substantial racial and ethnic disparities in SMM, mortality, and CVD burden, secondary objectives included evaluating SMM and mortality across racial and ethnic groups and assessing the population attributable fraction within each group. Lastly, subgroup analyses of SMM by underlying CVD diagnoses (eg, congenital heart disease, chronic heart failure) were performed. Variables used in the regression models included socioeconomic and demographic maternal characteristics, maternal comorbidities, and pregnancy-specific complications.

Results: Among 38,374,326 individuals with delivery hospitalizations, 203,448 (0.5%) had CVD. Patients with CVD had an increased risk of SMM (11.6 vs 0.7%, adjusted odds ratio [aOR] 12.5, 95% CI, 12.0-13.1) and maternal death (538 vs 5 per 100,000 delivery hospitalizations, aOR 44.1, 95% CI, 35.4-55.0) compared with those without CVD. Patients with chronic heart failure had the highest SMM risk (aOR 354.4, 95% CI, 301.0-417.3) among CVD categories. Black patients with CVD had a higher risk of SMM (aOR 15.9, 95% CI, 14.7-17.1) than those without CVD with an adjusted population attributable fraction of 10.5% (95% CI, 10.0-11.0%).

Conclusion: CVD in pregnancy is associated with increased risk of SMM and mortality, with the highest risk of SMM among patients with chronic heart failure. Although CVD affects less than 1% of the pregnant population, it contributes to nearly 1 in 10 SMM events in the United States.