Inclusion Criteria:  pregnant women, regardless of age, race diagnosed with pulmonary hypertension(PH) before pregnancy or during pregnancy diagnosed with PH by right heart catheterization or echocardiography diagnostic criteria of right heart catheterization: mean pulmonary artery pressure (mPAP) ≥ 25 mm Hg by right heart catheterization at rest diagnostic criteria of echocardiography: pulmonary artery systolic pressure (PASP)≥40 mm Hg time: from January 1, 2012 to December 31, 2021  Exclusion Criteria:  Patients with isolated exercise-induced PH (mean PAP <25 mm Hg at rest and >30 mm Hg at exercise) were excluded. pulmonary artery systolic pressure (PASP)<40 mmHg by echocardiography mean pulmonary artery pressure (mPAP) < 25 mm Hg by right heart catheterization at rest