Dietary supplementation with l-arginine or placebo in women with pre-eclampsia

Background. To investigate the effect of dietary intake of the NO‐donor l‐arginine on the diastolic blood pressure in women with pre‐eclampsia. Methods. A randomized double‐blind study was designed to compare the effect of l‐arginine and placebo in pre‐eclamptic women with gestational length ranging from 28+0 to 36+0 weeks. The women received orally 12 g of l‐arginine or placebo daily for up to 5 days. The primary end‐point was to identify a difference in diastolic blood pressure alteration between the two groups after 2 days of intervention. Secondary end‐points included the interval from study start to delivery, the proportion of women delivered after 2, 5 or 10 days from treatment start and mean birth weight. Results. There was no statistically significant alteration in diastolic blood pressure in the l‐arginine group compared with the placebo group after 2 days of treatment (p = 0.4). No differences in the proportions of women delivered by day 2, 5 or 10 after study start, in the mean interval from study start to delivery, or in mean birth weight percentile were observed between the two groups. Conclusions. Oral l‐arginine supplementation did not reduce mean diastolic blood pressure after 2 days of treatment compared with placebo in pre‐eclamptic patients with gestational length varying from 28 to 36 weeks. Whether l‐arginine treatment could be clinically beneficial for the mother or the fetus if started earlier in the disease process than for the women in our study remains to be seen.