CASE PRESENTATION: A 20-year old female, G1 P0, presented to the clinic at 13 week of gestation. She was diagnosed with PAH at 5 years of age after which she underwent atrial septostomy. At presentation, her PAH treatment included macitentan, tadalafil and subcutaneous (SC) trepostinil. Despite extensive counselling, she refused termination of pregnancy. All teratogenic medications were thus stopped and SC trepostinil was changed to intravenous epoprostenol. She did well until 25 weeks of gestation when on presenting with dyspnea and hemoptysis she was admitted to the intensive care unit. On examination, she was found to have respiratory rate of 25/min, oxygen saturation of 86%, jugular venous distension of 10 cm and a systolic grade 2/6 murmur at left lower sternal border. Arterial blood gas was remarkable for pH 7.47, pCO2 27 mm Hg, pO2 147 mm Hg while platelet count was noted to be 75 κ/μL. Echocardiogram revealed increase in systolic pulmonary artery (PA) pressure to 120 mm Hg from pre-gestation value of 80 mm Hg. At 26 weeks of gestation, due to fetal distress, emergent cesarean section was undertaken to deliver a healthy male infant. However, post-procedure she developed cardiac arrest with ventricular tachycardia and after 15 minutes of cardiopulmonary resuscitation, was placed on veno-arterial ECMO, ventilator and vasopressor support. Swan Ganz catheter was inserted that revealed PA pressure of 139/85 mm Hg, central venous pressure of 11 mm Hg, wedge pressure of 10 mm Hg and cardiac index of 2.1 L/min/m2. With use of ECMO and reinitiation of epoprostenol, ambrisentan and sildenafil, these hemodynamics improved. Despite complications such as recurrent hemoptysis and development of hemopericardium with tamponade, she slowly got better and vasopressor support was weaned off. ECMO support was decreased and eventually removed on postoperative day (POD) 24. Weaning from ventilator was unsuccessful and tracheostomy was done at POD 29. She was eventually transitioned to SC trepostinil and discharged on POD 101.