Background Women with polycystic ovary syndrome (PCOS) have an increased risk of pregnancy‐associated complications. However, data on peripartum cardiovascular complications remain limited. Hence, we investigated trends, outcomes, and predictors of cardiovascular complications associated with PCOS diagnosis during delivery hospitalizations in the United States. Methods and Results We used data from the National Inpatient Sample (2002–2019). International Classification of Diseases, Ninth Revision ( ICD‐9 ), or International Classification of Diseases, Tenth Revision ( ICD‐10 ), codes were used to identify delivery hospitalizations and PCOS diagnosis. A total of 71 436 308 weighted hospitalizations for deliveries were identified, of which 0.3% were among women with PCOS (n=195 675). The prevalence of PCOS, and obesity among those with PCOS, increased during the study period. Women with PCOS were older (median, 31 versus 28 years; P <0.01) and had a higher prevalence of diabetes, obesity, and dyslipidemia. After adjustment for age, race and ethnicity, comorbidities, insurance, and income, PCOS remained an independent predictor of cardiovascular complications, including preeclampsia (adjusted odds ratio [OR], 1.56 [95% CI, 1.54–1.59]; P <0.01), eclampsia (adjusted OR, 1.58 [95% CI, 1.54–1.59]; P <0.01), peripartum cardiomyopathy (adjusted OR, 1.79 [95% CI, 1.49–2.13]; P <0.01), and heart failure (adjusted OR, 1.76 [95% CI, 1.27–2.45]; P <0.01), compared with no PCOS. Moreover, delivery hospitalizations among women with PCOS were associated with increased length (3 versus 2 days; P <0.01) and cost of hospitalization ($4901 versus $3616; P <0.01). Conclusions Women with PCOS had a higher risk of preeclampsia/eclampsia, peripartum cardiomyopathy, and heart failure during delivery hospitalizations. Moreover, delivery hospitalizations among women with PCOS diagnosis were associated with increased length and cost of hospitalization. This signifies the importance of prepregnancy consultation and optimization for cardiometabolic health to improve maternal and neonatal outcomes.