Maternal and fetal outcomes in patients with congenital heart disease associated with pulmonary arterial hypertension in high-altitude areas: a retrospective cohort study

Objectives Pulmonary arterial hypertension associated with congenital heart disease (CHD-PAH) increases maternal and fetal risk. This study aimed to analyze maternal and fetal outcomes in patients with CHD-PAH in high-altitude areas. Methods The pregnant women with CHD were analyzed retrospectively from 2012 to 2022. Pulmonary artery systolic pressure (PASP) was estimated by echocardiography. Patients were categorized into four groups: no PAH (PASP < 40 mmHg), mild (40 mmHg≤PASP < 50 mmHg), moderate (50 mmHg≤PASP < 70 mmHg) and severe PAH (PASP ≥ 70 mmHg). Results 429 pregnant women were included in this study, 187 with no PAH, 102 with mild PAH, 79 with moderate PAH, 61 with severe PAH. The severe PAH group had the highest proportions of NYHA functional classes III/IV, SpO 2 <90%, and elevated NT-proBNP levels, but a lower rate of regular prenatal checkups compared with the no PAH and mild PAH groups ( P < 0.05). The severe PAH group showed significantly higher rates of low birth weight, preterm birth, and neonatal asphyxia ( P < 0.001). Independent risk factors for maternal and infant complications included NYHA functional classes III-IV (OR = 6.342, 95% CI: 2.28–17.894), NT-proBNP ≥ 250 ng/L (OR = 3.148, 95% CI: 1.121–8.840), moderate PAH (OR = 6.263, 95% CI: 1.657–23.669), and severe PAH (OR = 7.125, 95% CI: 1.792–28.334), whereas higher BMI was a protective factor (OR = 0.802, 95% CI: 0.712–0.904). Conclusions The level of PASP, NT-proBNP, and NYHA function class, BMI may be useful in risk stratification in pregnancy with CHD-PAH in high-altitude areas.