Long-Term Impact of Pregnancy on Clinical Outcomes in Individuals With Hypertrophic Cardiomyopathy

Background: The effect of pregnancy on individuals with hypertrophic cardiomyopathy (HCM) is not well investigated. Objectives: The purpose of this study was to assess the impact of pregnancy on all-cause mortality and clinical outcomes among individuals with HCM. Methods: Using the TriNetX research network, we identified individuals within reproductive age (≥18-45 years) with a diagnosis of HCM between 2012 and 2022 (n = 10,936). Patients were stratified based on pregnancy history into 2 groups: 1) those with a history of pregnancy/high-risk pregnancy supervision; and 2) those without a history of pregnancy or subsequent antenatal/pregnancy supervision encounters throughout the study period. Propensity score matching resulted in 3,399 patients in each cohort. The primary outcome was all-cause mortality. Secondary outcomes include a composite of arrhythmic events (defined as sudden cardiac death, appropriate shocks, sustained ventricular tachycardia/ventricular fibrillation), major adverse cardiovascular events (MACE), and acute heart failure exacerbation during 10 years of follow-up. Results: Pregnancy in patients with HCM was associated with a comparable risk of all-cause mortality (adjusted OR: 0.89; 95% CI: 0.7-1.14; P = 0.37) at 10-year follow-up. There was no difference in MACE (adjusted OR: 1.02; 95% CI: 0.85-1.22; P = 0.80) and arrhythmic events (adjusted OR: 0.93; 95% CI: 0.73-1.18; P = 0.55) between both groups. In subgroup analysis of obstructive HCM, the findings were similar between both pregnancy and no pregnancy groups. Conclusions: Pregnancy in individuals with HCM was not associated with a higher risk of adverse outcomes at long-term follow-up. Further efforts are warranted to better understand the short-term outcomes in this high-risk population.