Comparison of Perinatal Outcomes and Delivery Strategies in Pregnant Women with Idiopathic vs. Secondary Pulmonary Arterial Hypertension: A Retrospective Cohort Study

Objective: To compare the clinical characteristics, peripartum management, and maternal and fetal outcomes between pregnant women with idiopathic pulmonary arterial hypertension (iPAH) and those with secondary pulmonary arterial hypertension. Methods: This was a retrospective cohort study. A total of 184 pregnant patients with PAH were admitted to West China Second University Hospital from 2014–2024. Patients were divided into iPAH (n=46) and secondary PAH (n=138) groups on the basis of the etiology of PAH. Demographic and clinical data extracted from medical records included maternal demographics, clinical characteristics, mode of delivery, anesthesia methods, postpartum complications, and fetal/neonatal outcomes. Results: The median maternal age was 29.54 years, with 25% iPAH cases and 75% secondaryPAH cases. The majority (92.9%) were diagnosed during pregnancy. Compared with secondary PAH patients, iPAH patients had a greater average age (31.35 vs. 28.93 years, p =0.003) and BMI (26.05 vs. 24.15 kg/m ² , p =0.003) but lower systolic pulmonary artery pressure (sPAP) (50.12 vs. 58.04 mmHg, p =0.008). Cesarean section was the predominant delivery method (99.3%), with 97.6% of iPAH patients and 91.1% of secondary PAH patients receiving spinal anesthesia. Intraoperative blood loss was greater in the iPAH group (539.29 vs. 388.31 mL, p <0.001). The overall in-hospital survival rate was 98.9%, with a maternal mortality rate of 1.1%. The fetal outcomes included a preterm birth rate of 52.9% and low birth weight in 49% of the neonates. No significant differences in neonatal outcomes were detected between the iPAH and secondary PAH groups. Conclusion: Despite multidisciplinary management improving survival, iPAH pregnancies are associated with increased maternal mortality and heart failure risks. Cesarean delivery with tailored hemostasis and cautious oxytocin use optimizes outcomes. Early prenatal screening, especially in high-risk women (advanced age, obesity), and phenotype-specific protocols are critical to mitigate risks. The limitations of this study include its retrospective design and echocardiography-based PAH diagnosis.