Pregnancy related complications in women with hypertrophic cardiomyopathy: a nationwide population-based cohort study

Background The impact of hypertrophic cardiomyopathy (HCM) on cardiovascular and obstetrical outcomes in pregnant women remains unclear, particularly in Asian populations. This study aimed to evaluate the maternal cardiovascular and obstetrical outcomes in Korean women with HCM. Methods Using data from the Korean National Health Insurance Service database, we identified women who gave birth via cesarean section or vaginal delivery after being diagnosed with HCM between 2006 and 2019. Maternal cardiovascular and obstetrical outcomes were assessed based on the trimester of pregnancy. Results This study included 122 women and 158 pregnancies. No maternal deaths were noted; however, 21 cardiovascular events, such as hospital admission for cardiac problems, including heart failure and atrial fibrillation (AF), new-onset AF or ventricular tachycardia (VT) occurred in 14 pregnancies (8.8%). Cardiac events occurred throughout pregnancy with a higher occurrence in the third trimester. Cesarean sections were performed in 49.3% of the cases, and all cardiovascular outcomes occurring after delivery were observed in patients who had undergone cesarean sections. Seven cases involved preterm delivery, and two of these cases were accompanied by cardiac events, specifically AF. Pre-existing arrhythmia (AF: odds ratio (OR): 7.44, 95% confidence interval (CI): 2.61-21.21, P < 0.001; VT: OR: 31.61, 95% CI: 5.85-172.77, P < 0.001) was identified as a predictor for composite outcomes of cardiovascular events or preterm delivery. Conclusions Most pregnant women with HCM were well-tolerated. However, cardiovascular complications could occur in some patients. Therefore, planned delivery may be necessary for selected patients, especially the women with pre-existing arrhythmias.