ObjectiveThe objective was to investigate maternal, obstetric, and neonatal outcomes of pulmonary hypertension (PH) in pregnancy based on different altitudes of residence in the southwest plateau area of China. MethodsData were collected from pregnant women with PH admitted to The First People's Hospital of Yunnan Province from January 1, 2012, to December 31, 2021. All pregnant women with PH were diagnosed via echocardiography according to a pulmonary arterial systolic pressure > 30 mmHg. Patients were classified into three groups according to the altitude of residence during pregnancy. Demographic characteristics, maternal and neonatal outcomes, complications, and follow-up outcomes after discharge were reported. ResultsFifty-two pregnant women with PH were included. Among the included women, eleven (21.2%) were in the low-altitude group, twenty-six (50.0%) were in the medium-altitude group, and fifteen (28.8%) were in the high-altitude group. The overall mortality rate was 5.8%: death up to 6 weeks after delivery occurred in one patient (1.9%), and the other two patients (4.9%) died within one to four years after delivery. Preterm delivery occurred in 22 (42.3%) patients. The incidences of maternal death (11.5% vs. 0.0, p < 0.01), cesarean delivery (80.8% vs. 70.7% vs. 80.0%, p = 0.001), and live birth (84.6% vs. 72.7% vs. 80.0%, p < 0.01) were higher in the medium-altitude group than in the low- and high-altitude groups. Therapeutic abortion was performed in 15.4% of the women, with the highest rate in the high-altitude group (p < 0.01). The rates of heart failure and respiratory failure were highest in the low-altitude group (p < 0.01). No fetal death occurred, and 22 neonates (42.3%) had a low birth weight. During a median follow-up of 2.4 years, two patients died (4.9%), and seven (17.1%) still had PH. ConclusionThe in-hospital mortality rate of pregnant women with PH in the plateau area is similar to that previously reported in the low-altitude region, but the long-term survival rate is lower. Therapeutic abortion is also higher in pregnant women with a high altitude of residence. These findings highlight that the risks associated with PH in pregnancy persist beyond delivery and underscore the importance of early risk assessment, rigorous multidisciplinary management, and prolonged postpartum follow-up, especially in plateau populations with limited access to specialized care.