Maternal pulmonary hypertension and cardiopulmonary outcomes during delivery hospitalization in the United States: A nationwide study from 2016–2020

•Maternal pulmonary hypertension prevalence is rising in the United States despite being considered a pregnancy contraindication.•In this nationwide study, maternal pulmonary hypertension was strongly associated with adverse maternal cardiopulmonary outcomes during delivery hospitalization.•These patients should ideally receive peripartum care at specialized centers with high-acuity capabilities in a multidisciplinary setting. Maternal pulmonary hypertension can pose substantial morbidity and mortality risks, particularly during labor and delivery. Although maternal pulmonary hypertension is conventionally considered a contraindication to pregnancy, advances in the management of pH may contribute to improving outcomes. In this nationwide study, we aim to characterize the prevalence of maternal pulmonary hypertension in the United States and its association with adverse cardiopulmonary outcomes during delivery hospitalizations. In this cross-sectional cohort study, we analyzed delivery hospitalizations in the National Inpatient Sample from 2016 to 2020. The primary exposure was maternal pulmonary hypertension. The primary outcome was a composite of maternal cardiopulmonary morbidity events during the delivery hospitalization including: death, heart failure, intraoperative heart failure, pulmonary edema, cardiac arrest, myocardial infarction, ventricular fibrillation, respiratory failure, pneumonia, acute kidney injury, and cardiac conversion. Propensity score matching was used to estimate the association between maternal pulmonary hypertension and adverse cardiopulmonary outcomes, adjusting for sociodemographic variables and validated clinical comorbidities as covariates. Secondary outcomes included mechanical circulatory support utilization, length of stay, and total hospitalization costs. Among 18,161,315 delivery hospitalizations, 4,630 patients had pulmonary hypertension, yielding a maternal pulmonary hypertension prevalence of 25 per 100,000 delivery hospitalizations with a yearly trend of increasing prevalence (odds ratio = 1.06, 95 % CI 1.01 to 1.11, P = 0.028). After propensity score matching to create well-balanced groups, 4,560 patients with pulmonary hypertension were compared to 4,560 patients without pulmonary hypertension. In this confounder-adjusted analysis, the primary composite outcome of cardiopulmonary morbidity and mortality occurred in 41.1 % of the PH group compared to 14.4 % in the no PH group (adjusted odds ratio = 4.16, 95 % CI 3.3