L-Arginine Supplementation in Patients with Gestational Hypertension: A Pilot Study

Objective: To evaluate the effects of L-arginine (L-Arg) supplementation on clinical outcomes and blood pressure (BP) changes in patients with gestational hypertension. Methods: Patients with gestational hypertension and proteinuria (n?=?28, >300mg/24 h) and those without proteinuria (n?=?46) were randomized in a double-blind design to receive either L-Arg (20g/500 mL intravenously daily, for 5 days followed by 4g/day orally for 2 weeks) or placebo (PL). The primary outcome variable was time from randomization to delivery (Latency). Automated BP readings were obtained every 2 hours, between 8.00 am and 8.00 pm daily, untill the sixth day after treatment. Results: At inclusion, gestational age and proportions of patients with proteinuria did not differ significantly between the PL and L-Arg group. Latency was significantly longer in the L-Arg group compared with the PL group (19.5 ± 16.9 vs. 31.7 ± 25.2 days; p?=?0.008). Compared with baseline, both systolic and diastolic BP 6 days after treatment were significantly reduced in the L-Arg group but not in the PL group. The subgroup of patients without proteinuria randomized to the group receiving L-Arg showed a trend to prolong pregnancy, to attenuate the evolution to PE, and to reduce the rate of low birth weight. Conclusions: The treatment with L-Arg seems promising in prolonging pregnancy and reducing blood pressure, particularly in patients with gestational hypertension and without proteinuria. This benefit should be confirmed in larger studies with the power to evaluate the effectiveness of L-Arg in preventing the development to preeclampsia.