Dietary Supplement Cuts Risk of Preeclampsia

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Pregnant women at risk for preeclampsia who used supplements containing

L-arginine and antioxidant vitamins significantly lowered their risk for

this gestational complication, a randomized trial found.

Women who consumed food bars containing the amino acid L-arginine plus

antioxidants had an absolute risk reduction for preeclampsia and eclampsia

of 0.17 (95% CI 0.12 to 0.21, *P*<0.001) compared with placebo, according to

Felipe Vadillo-Ortega, MD, of City University in Mexico City, and

colleagues.

In comparison, those who were given bars containing only antioxidant

vitamins had a nonsignificant absolute risk reduction of 0.07 (95% CI 0.005

to 0.15, *P*=0.052), the investigators reported online in *BMJ*.

" This relatively simple and low-cost intervention may have value in reducing

the risk of preeclampsia and associated preterm birth, " the investigators

observed.

Inadequate perfusion of the uterus and placenta leading to vasoconstriction

and endothelial activation are thought to underlie the processes that result

in preeclampsia.

L-arginine is the substrate for the production of the vasodilator nitric

oxide, and pregnancy can result in inadequate levels of this amino acid.

To determine if L-arginine supplementation could provide a source for nitric

oxide and thereby help prevent preeclampsia, Vadillo-Ortega and

co-investigators enrolled 672 women seen at a single center between 2001 and

2005.

All were considered to be at risk, in that they had a history of

preeclampsia or a first-degree relative with such a history.

Women entered the study between gestational weeks 14 and 32, and had a

median of five clinic visits.

The number needed to treat in the L-arginine group was 5.73 (95% CI 4 to

10), while the number needed in the antioxidant group was 13.06 (95% CI 6 to

200).

The risk was decreased in women who began treatment before 24 weeks (RR

0.37, 95% CI 0.23 to 0.58), but not in those who began treatment later (RR

0.64, 95% CI 0.30 to 1.37), the investigators found.

There also was an absolute risk reduction of 0.09 in preterm birth in the

L-arginine group compared with placebo (RR 0.53, 95% CI 0.33 to 0.84, *P*

=0.003).

The groups were similar on other secondary endpoints such as mean birth

weight and placental abruption.

Five neonatal deaths associated with extreme prematurity occurred: Three in

the antioxidant group and two in the placebo group.

None of the mothers died.

Significantly more women in the L-arginine group reported side effects with

the treatment:

- Nausea, RR 1.25 (95% CI 1.04 to 1.51, *P*=0.019)

- Dyspepsia, RR 1.34 (95% CI 1.02 to 1.77, *P*=0.04)

- Dizziness, RR 1.42 (95% CI 1.02 to 1.97, *P*=0.039)

- Palpitations, RR 1.36 (95% CI 1.05 to 1.76, *P*=0.019)

- Headache, RR 1.26 (95% CI 1.06 to 1.51, *P*=0.01)

A limitation of the study is its generalizability because this cohort had a

high prevalence of recurrent preeclampsia.

Further study will be needed to replicate the results in other populations,

the authors noted.

Another weakness was the use of combination L-arginine and antioxidants, so

the relative contributions of the individual components cannot be

determined.

An additional concern, the binary nature of the primary outcome, was raised

by Liam Smeeth, MD, PhD, of the London School of Hygiene and Tropical

Medicine, and , MBBS, PhD, of University College London, in an

accompanying editorial.

Much of the relative risk reduction was seen in a few women whose blood

pressure just crossed the threshold to qualify for preeclampsia, they

explained.

" Such a simple divide is a poor reflection of the underlying biology:

preeclampsia is not an 'all or nothing' disease, and a more nuanced approach

suggests quite modest effects overall, " wrote Smeeth and .

The editorialists called for further exploration of the effects of

L-arginine in preeclampsia and research into potential mechanisms of action

with, and without, antioxidant vitamins.

LINK<http://www.medpagetoday.com/OBGYN/Pregnancy/26588?utm_content= & utm_medium=e\

mail & utm_campaign=DailyHeadlines & utm_source=WC & userid=134896>

*Primary source: *BMJ

Source reference:

Vadillo-Ortega F, et al " Effect of supplementation during pregnancy with

L-arginine and antioxidant vitamins in medical food on preeclampsia in high

risk population: randomized controlled trial " *BMJ* 2011; DOI:

10.1136/bmj.d2901. <http://www.bmj.com/content/342/bmj.d2901.full>

*Additional source:* BMJ

Source reference:

Smeeth L, D " Can a dietary supplement prevent preeclampsia? "

*BMJ*2011; DOI:

10.1136//bmj.d2777.<http://www.bmj.com/content/342/bmj.d2777>

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