Pregnancy outcomes and risk factors for adverse cardiac events in women with congenital heart disease complicated by pulmonary hypertension

Background With advancements in the diagnosis and treatment of congenital heart disease (CHD), an increasing number of women with CHD survive to childbearing age and pursue pregnancy. However, CHD complicated by pulmonary hypertension (PH) significantly elevates the risk of adverse pregnancy outcomes. The relationship between PH severity and specific outcomes, such as heart failure and obstetric complications, remains unclear, and evidence-based risk stratification criteria based on PH classification, cardiac function, and maternal characteristics are lacking. This study compared pregnancy outcomes and risk factors in CHD patients with no PH, mild-to-moderate PH, and severe PH, aiming to clarify the association between PH severity and adverse events and establish risk stratification criteria for individualized management. Methods This single-center retrospective study included 849 pregnant women diagnosed with CHD at our hospital between January 2023 and December 2024. Patients were stratified into three groups: 613 without PH, 194 with mild-to-moderate PH, and 42 with severe PH. Echocardiographic data, demographic characteristics, clinical parameters, and pregnancy outcomes were collected. Adverse pregnancy outcomes were defined as maternal death, heart failure, other cardiac complications, obstetric complications, or neonatal adverse events. Incidence rates of adverse outcomes were compared across groups, and risk factors were analyzed. Results Adverse pregnancy outcomes occurred in 23 (3.8%), 10 (5.2%), and 6 (14.3%) patients in the no-PH, mild-to-moderate PH, and severe PH groups, respectively. CHD patients with PH exhibited worse pregnancy outcomes compared to those without PH. Severe PH was associated with significantly higher rates of heart failure (7.1% vs. 2.1% vs. 0.13%), obstetric complications (5.8% vs. 2.1% vs. 1.6%), and other cardiac complications (2.4% vs. 1.0% vs. 0.3%) compared to mild-to-moderate PH and no-PH groups. Multivariate analysis identified severe PH (OR=4.2, 95% CI: 2.1–8.5), reduced left ventricular ejection fraction (LVEF <50%, OR=3.8, 95% CI: 1.9–7.6), New York Heart Association (NYHA) class III-IV (OR=5.1, 95% CI: 2.5–10.4), and advanced maternal age (>37 years, OR=2.7, 95% CI: 1.3–5.6) as independent risk factors for adverse cardiac events (P<0.001). Conclusions CHD patients with PH face a significantly elevated risk of adverse pregnancy outcomes, with risk escalating in parallel with PH severity. Severe PH, reduced LVEF, NYHA class III-IV, and advanced maternal age (>37 years) are independent predictors of adverse cardiac events. These findings underscore the need for multidisciplinary management and early intervention in high-risk populations.