Abstract Body (Do not enter title and authors here): Background:
Pregnancy-related hypertensive disorders are major risk factors for peripartum cardiomyopathy (PPCM). Although aspirin is recommended during pregnancy to reduce the risk of severe preeclampsia/ eclampsia, its role in preventing PPCM remains unknown.

Methods:
Using the TriNetX network, we identified pregnant women with pregnancy-related hypertensive disorders. Those with a diagnosis of heart failure with reduced ejection fraction before pregnancy were excluded. Patients were categorized into two cohorts: those who received aspirin during pregnancy and those who did not. Outcomes, including PPCM, heart failure hospitalization, all-cause mortality, and all-cause hospitalization, were assessed at 1-year follow-up after delivery. Cohorts were propensity score-matched based on age and medical comorbidities.

Results:
Out of 446,239 eligible pregnant women with pregnancy-related hypertensive disorders, a propensity score–matched cohort of 59,877 patients who received aspirin (mean age 31.2 ± 5.9 years) and 59,877 who did not (mean age 31.3 ± 5.9 years) was identified for comparative analysis. The aspirin group showed no significant difference in peripartum cardiomyopathy (0.32 vs. 0.28%; hazard ratio [HR], 1.11; 95% confidence interval [CI], 0.90-1.36; p=0.35), heart failure hospitalization (2.44% vs. 2.41%; HR, 1.00; 95% CI, 0.93-1.07; p=0.89), and all-cause mortality (0.12% vs. 0.14%; HR, 0.80; 95% CI, 0.59-1.10; p=0.17) compared the no-aspirin group. Aspirin use was associated with a higher risk of all-cause hospitalization (37.44% vs. 30.89%; HR, 1.22; 95% CI, 1.20-1.25; p<0.01) than the no-aspirin group.

Conclusion:
Among pregnant women with pregnancy-related hypertensive disorders, aspirin use was not effective in preventing peripartum cardiomyopathy, heart failure hospitalization, and all-cause mortality.