oxidants and antioxidants in biology - Oxygen Club of California

Vitamin E in pregnacy and pre-eclampsia
F.J. KELLY
on behalf of Vitamins In Pre-eclampsia (VIP) study team,
School of Health & Life Sciences, Kings’ College London, UK
Pregnancy is associated with marked changes in lipid metabolism
and there is a general state of oxidative stress. In women who
develop pre-eclampsia this oxidative stress is magnified and indeed,
may underlie the development of the condition. Evidence to
support this was obtained in an intervention trial in which women
at risk of developing pre-eclampsia received vitamin C (1000
mg/day) and vitamin E (400 IU/day) supplements or placebo.
(Chappell et al, Lancet 354:810-6, 1999). Increased risk of preeclampsia
was determined by abnormal uterine artery Doppler
waveform analysis or pre-eclampsia in the previous pregnancy. 79
women identified as ‘at risk’ received vitamin supplements and 81
received placebos. These were compared with 33 low risk women
not taking supplements. Blood samples were obtained every 4
weeks from 20 weeks’ gestation until delivery. Those receiving
vitamins were found to have a markedly reduced incidence of preeclampsia.
This clinical benefit was associated with improvement
in a range of markers of placental insufficiency and oxidative
stress. For example, markers of oxidative stress and placental
function were abnormal in the placebo group; compared to the low
risk women, ascorbic acid concentrations were 28% lower (95% CI
15% to 40%) and 8-epi-PGF 2α 49% higher (CI 8 % to 104%). In
the vitamin supplemented group, concentrations of ascorbic acid,
8-epi-PGF 2α , leptin and PAI-1/PAI-2 were not significantly different
from the low risk group. These findings are now being followed-up
in a number of multi-centre studies to determine if antioxidant
supplementation of women at risk of pre-eclampsia is associated
with improved clinical outcome, supporting a rationale for
prophylactic vitamin C and E.
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