The research reported that supplementation with the amino acid L-arginine and antioxidant vitamins during pregnancy reduced the incidence of pre-eclampsia in women at high risk of the condition.
“The incidence of pre-eclampsia was reduced significantly in women randomised to L-arginine plus antioxidant vitamins compared with placebo,” said the authors, led by Professor Felipe Vadillo-Ortega from the School of Medicine at Universidad Nacional, Mexico.
“This relatively simple and low cost intervention may have value in reducing the risk of pre-eclampsia and associated preterm birth,” they added.
In an accompanying BMJ editorial, Professor Liam Smeeth and Dr David Williams from the London School of Hygiene and Tropical Medicine, and the Institute for Women’s Health, at University College London Hospital, said that although L-arginine with vitamins shows promise for the prevention of pre-eclampsia, “there are good grounds for caution.”
“L-arginine is a widely available food supplement so the implications of this result could be profound. However, several concerns suggest that a cautious interpretation is warranted,” they said.
Maternal risk
Pre-eclampsia is a condition where abnormally high blood pressure and other disturbances develop during pregnancy. It affects about 5% of all first-time pregnancies and is dangerous for both mother and child.
The condition is among the leading causes of maternal and neonatal death and ill health. The highest incidence of maternal death from pre-eclampsia is in Latin America and the Caribbean, where it accounts for a quarter of mortalities.
Previous research has suggested that a relative deficiency the amino acid L-arginine – which plays a role maintaining healthy blood flow through the production of nitric oxide – could be associated with the development of pre-eclampsia.
The new study, a randomised, blinded, placebo controlled clinical trial tested a combination of L-arginine and antioxidant vitamins for their ability to prevent the development of pre-eclampsia in high risk women.
Study details
Supplementation with food bars containing either L-arginine plus antioxidant vitamins, antioxidant vitamins alone, or placebo were given to 672 women at high risk of pre-eclampsia during pregnancy.
Supplementation began when women were between 14-32 weeks pregnant, and continued until delivery. Blood pressure and L-arginine levels were measured every three to four weeks at the hospital clinic.
Prof. Vadillo-Ortega and his team reported the incidence of pre-eclampsia to be significantly reduced in women randomised to L-arginine plus antioxidant vitamins compared with placebo (absolute risk reduction of 17 percent).
They added that antioxidant vitamins alone “showed an observed benefit, but this effect was not statistically significant compared with placebo”.
L-arginine plus antioxidant vitamins compared with antioxidant vitamins alone also resulted in a significant reduction in the risk of developing pre-eclampsia.
In addition the authors noted a secondary study finding; that L-arginine plus antioxidant vitamin supplementation resulted in a significant reduction in the risk of indicated preterm birth compared with placebo. They noted that this supported their findings as pre-eclampsia is a major risk factor for pre-term births.
Protective effect
Vadillo-Ortega and his colleagues said that their findings suggest a simple and low cost prevention for pre-eclampsia, but noted that their findings should now be evaluated in a low risk population “to determine the generalisability of the protective effect.”
In their accompanying editorial (BMJ, doi: 10.1136/bmj.d2777), Smeeth and Williams said:
“Despite its simple definition, pre-eclampsia is a complex syndrome with multiple causes that can present with a variety of clinical features. For this reason, a single treatment is unlikely to be effective in all women at risk.”
They added that before more trials are started, a rigorous systematic review “of the numerous inconsistent strands of evidence relating to L-arginine and its possible effects on pre-eclampsia” is needed.
Source: British Medical Journal
Published online ahead of print, doi: 10.1136/bmj.d2901
“Effect of supplementation during pregnancy with L-arginine and antioxidant vitamins in medical food on pre-eclampsia in high risk population: randomised controlled trial”
Authors: F. Vadillo-Ortega, O. Perichart-Perera, S. Espino, M.A. Avila-Vergara, I. Ibarra, et al