Association between pregnancy and long-term cardiac outcomes in individuals with congenital heart disease.

BACKGROUND: As early life interventions for congenital heart disease improve, more patients are living to adulthood and are considering pregnancy. Scoring and classification systems predict the maternal cardiovascular risk of pregnancy in the context of congenital heart disease, but these scoring systems do not assess the potential subsequent risks following pregnancy. Data on the long-term cardiac outcomes after pregnancy are unknown for most lesion types. This limits the ability of healthcare practitioners to thoroughly counsel patients who are considering pregnancy in the setting of congenital heart disease.

OBJECTIVE: We aimed to evaluate the association between pregnancy and the subsequent long-term cardiovascular health of individuals with congenital heart disease.

STUDY DESIGN: This was a retrospective longitudinal cohort study of individuals identifying as female who were receiving care in two adult congenital heart disease centers from 2014 to 2019. Patient data were abstracted longitudinally from a patient age of 15 years (or from the time of entry into the healthcare system) to the conclusion of the study, death, or exit from the healthcare system. The primary endpoint, a composite adverse cardiac outcome (death, stroke, heart failure, unanticipated cardiac surgery, or a requirement for a catheterized procedure), was compared between parous (at least one pregnancy >20 weeks' gestation) and nulliparous individuals. By accounting for differences in the follow-up, the effect of pregnancy was estimated based on the time to the composite adverse outcome in a proportional hazards regression model adjusted for the World Health Organization class, baseline cardiac medications, and number of previous sternotomies. Participants were also categorized according to their lesion type, including septal defects (ventricular septal defects, atrial septal defects, atrioventricular septal defects, or atrioventricular canal defects), right-sided valvular lesions, left-sided valvular lesions, complex cardiac anomalies, and aortopathies, to evaluate if there is a differential effect of pregnancy on the primary outcome when adjusting for lesion type in a sensitivity analysis.

RESULTS: Overall, 711 individuals were eligible for inclusion; 209 were parous and 502 nulliparous. People were classified according to the World Health Organization classification system with 86 (12.3%) being classified as class I, 76 (10.9%) being classified as class II, 272 (38.9%) being classified as class II to III, 155 (22.1%) being classified as class III, and 26 (3.7%) being classified as class IV. Aortic stenosis, bicuspid aortic valve, dilated ascending aorta or aortic root, aortic regurgitation, and pulmonary insufficiency were more common in parous individuals, whereas dextro-transposition of the great arteries, Turner syndrome, hypoplastic right heart, left superior vena cava, and other cardiac diagnoses were more common in nulliparous individuals. In multivariable modeling, pregnancy was associated with the composite adverse cardiac outcome (36.4%% vs 26.1%%; hazard ratio, 1.83; 95% confidence interval, 1.25-2.66). Parous individuals were more likely to have unanticipated cardiac surgery (28.2% vs 18.1%; P=.003). No other individual components of the primary outcome were statistically different between parous and nulliparous individuals in cross-sectional comparisons. The association between pregnancy and the primary outcome was similar in a sensitivity analysis that adjusted for cardiac lesion type (hazard ratio, 1.61; 95% confidence interval, 1.10-2.36).

CONCLUSION: Among individuals with congenital heart disease, pregnancy was associated with an increase in subsequent long-term adverse cardiac outcomes. These data may inform counseling of individuals with congenital heart disease who are considering pregnancy.