Vitamin C No Help for Preeclampsia
Vitamins C and E Offer No Protection Against Pregnancy-Related High Blood Pressure Disorders, Study Finds
April 8, 2010 -- Taking high doses of vitamins C and E does not protect
against a common and potentially fatal high blood pressure disorder during
pregnancy, a large, government study confirms.
More than 10,000 pregnant women took part in the National Institutes of
Health-funded trial, designed to determine if average-risk women could lower
their risk of developing preeclampsia by taking vitamin C and E supplements
starting early in pregnancy.
Several small studies reported in the 1990s suggested a role for vitamin C
and E in the prevention of preeclampsia and other pregnancy-related high blood
pressure disorders, but the large trial failed to show any benefit.
The findings appear in the April 8 issue of the New England Journal of
“The study results effectively rule out vitamin C and E supplements as a
means to prevent the hypertensive disorders during pregnancy,” Alan Guttmacher,
MD, of the National Institute of Child Health and Human Development (NICHD),
says in a news release.
Preeclampsia Endangers Mother, Baby
Occurring in between 5% and 8% of pregnancies, preeclampsia is characterized
by dangerously high increases in blood pressure coupled with a rise in protein
in the urine indicative of kidney stress.
The condition typically occurs after the 20th week of pregnancy, but it can
Preeclampsia affects the placenta, and it is a leading cause of childbirth
complications, including low-birth weight, premature birth, and stillbirth.
It is also the second leading cause of pregnancy-related maternal deaths in
the U.S., according to National Heart Lung and Blood Institute (NHLBI), which
co-funded the study with NICHD.
The cure for preeclampsia is delivery, and there is no proven way to prevent
The causes of pregnancy-related hypertension are poorly understood, but one
theory suggests that damage from molecules known as free radicals plays a role.
Free radicals occur as a byproduct when the body uses oxygen.
Antioxidants like vitamins C and E interfere with free radicals and are
thought to reduce free radical damage.
The Study Findings
In the newly published study, all the enrolled women were delivering for the
Study co-author Catherine Y. Spong, MD, tells WebMD that first-time moms
have a greater risk for preeclampsia than women who have had previous
All the participants were considered healthy at enrollment, with no evidence
high blood pressure or protein in the urine. And all were enrolled no later
than their 15th week of pregnancy.
About 5,000 women were randomly assigned to take 1,000 milligrams of vitamin
C and 400 IU of vitamin E daily for the rest of their pregnancy, or about 10
times the amount of C and E in the typical prenatal vitamin.
The remaining 5,000 took placebo capsules that looked exactly like the
vitamins. Neither the women nor the researchers knew which treatment was being
given while the trial was going on.
After all the women had delivered, the researchers reported no significant
difference in preeclampsia, other high blood pressure disorders, or adverse
birth outcomes between the vitamin- and placebo-treated groups.
The findings make it clear that high doses of vitamins C and E have little
impact on hypertension risk during pregnancy, but this does not mean pregnant
women should not take prenatal vitamins, Spong says.
“Women who want to reduce their preeclampsia risk should not be taking
additional doses of vitamins C and E,” Spong says. “But women should eat a
well-balanced diet when they are pregnant and they should take a prenatal