Pulmonary hypertension during pregnancy carries high mortality rate. The relatively long-acting, specific pulmonary vasodilator treprostinil has been used to improve survival in these parturients. Slow uptitration is performed in most cases, and rapid titration has not been reported in the postpartum period. We retrospectively reviewed 17 pregnant patients with severe pulmonary arterial hypertension who were treated with intravenous treprostinil in our institution between 2014 and 2016. Patients' demographic characteristics, etiology, functional status, mode of delivery, anesthetic administration, medical therapy, echocardiographic and hemodynamic measurements, subsequent clinical course, and maternal-fetal outcomes were assessed. The a priori primary outcome is maternal mortality in this study. Rapid titration of intravenous treprostinil was initiated at 1.25 ng/kg/min and increased to effective dose of 10 ng/kg/min by 1.25-2.5 ng/kg/min every 3 hours. In the next 24 hours, we adjusted the dosage to a median maximum dose of 15 ng/kg/min (interquartile range, 15-20 ng/kg/min) over a median uptitration period of 34 hours (interquartile range, 24-41 hours) for 17 parturients with severe pulmonary hypertension. Treprostinil was weaned off by 0.50-1.25 ng/kg/min every 3 hours in 94.3 ± 42.4 hours. Fifteen patients survived to discharge, and only 2 patients died of pulmonary hypertensive crisis (maternal mortality rate, 11.7%). No treprostinil infusion-related postpartum complication was observed. Our experience suggested that rapid uptitration of intravenous treprostinil combined with oral sildenafil in the postpartum period may be a safe and effective approach for these very sick parturients with severe pulmonary hypertension.