Background: Women with polycystic ovary syndrome (PCOS) have increased risk of pregnancy-associated complications. However, there is scarcity of data on the trends, outcomes, and predictors of cardiovascular (CV) complications associated with PCOS diagnosis during delivery hospitalizations in the United States. Methods and Results: We used data from the National Inpatient Sample. ICD-9 or ICD-10 codes were used to identify delivery hospitalizations and PCOS diagnosis. A total of 71,436,308 weighted US hospitalizations for deliveries were identified from 2002 to 2019. Of the included hospitalizations, 0.3% were among women with PCOS (n=195,675). PCOS women were older (mean 30 vs 28 years, p<0.01) and had higher prevalence of diabetes, obesity, and dyslipidemia. After adjustment for age, race/ethnicity, comorbidities, insurance status and median household income, PCOS remained an independent predictor of CV complications at delivery including preeclampsia (aOR 1.56, 95% CI 1.54-1.59, p<0.01), eclampsia (aOR 1.58, 95% CI 1.54-1.59, p<0.01), peripartum cardiomyopathy (aOR 1.79, 95% CI 1.49-2.13, p<0.01), and heart failure (aOR 1.76, 95% CI 1.27-2.45, p<0.01) (Figure, Panel A), compared to no PCOS. An increase in overall prevalence of PCOS, and of obesity among those with PCOS, was also observed during the study period (Figure, Panel B). Moreover, delivery hospitalizations with PCOS diagnosis were associated with increased length (3 vs 2 days, p<0.01) and cost of hospitalization ($6,310 vs $4,468, p<0.01). Conclusions: Over a 17-year period, prevalence of PCOS and obesity increased among childbearing U.S. women. Women with PCOS had higher risks of preeclampsia/eclampsia, peripartum cardiomyopathy, heart failure, pulmonary edema, and venous thromboembolism. Moreover, delivery hospitalizations with PCOS diagnosis were associated with increased length and cost of hospitalization. Strategies to optimize pre-pregnancy cardiometabolic health may be particularly important to improve maternal CV outcomes.