November 30, 2007

Extra Doses of Vitamins C, E Don't Guard Against Preeclampsia

FRIDAY, Nov. 30 (HealthDay News) -- Taking extra doses of vitamins E and C doesn't reduce the chances of the blood pressure disorder preeclampsia in women who are at risk for the dangerous pregnancy complication, a new report finds.

The study casts real doubt on the effectiveness of this regimen in preventing preeclampsia, said study author Dr. Joseph A. Spinnato II, a professor of obstetrics and gynecology at the University of Cincinnati College of Medicine. "There were those that were arguing that the evidence was enough prior to our publication, so I think this is added weight," he said.

There may be other avenues of hope, however.

"The article was compelling and a little disappointing, but the authors left us with an out at the end of the article, that perhaps we shouldn't give E and C at the same time because the E might negate the C," said Dr. Miriam Greene, an assistant professor of obstetrics and gynecology at New York University School of Medicine in New York City. "You can continue and try to do the two separately. They did prove that the drugs were safe."

The findings appears in the December issue of Obstetrics & Gynecology.

Preeclampsia, which occurs in about 5 percent of all pregnant women in the United States, can lead to sudden high blood pressure and irregular blood flow. This can activate platelets and the clotting system, which in turn slows blood flow further.

Risk factors for preeclampsia include: first pregnancy, 10 years since previous pregnancy, carrying multiple fetuses, being overweight, being under 20 or over 35, or having a history of high blood pressure, diabetes, kidney disease, lupus or preeclampsia in a previous pregnancy, according to the March of Dimes.

At present, medical professionals have no clear guidance on how to prevent this potentially fatal condition.

"We don't have a good way to reduce the incidence of preeclampsia, except in calcium-deficient populations and those tend not to be in the U.S.," Spinnato said. "There is some evidence that still supports the use of baby aspirin among patients at risk, but even that is argued pretty heavily."

An Australian study published last year also found no benefit to vitamin C and E supplementation.

The current study involved 707 women at four Brazilian sites who were in their second trimester of pregnancy and who had chronic hypertension or a prior history of preeclampsia.

The women were randomly assigned to receive 1,000 milligrams of vitamin C with 400 International Units of vitamin E or a placebo daily.

The rate of preeclampsia was 13.8 percent in the vitamin group and 15.6 percent in placebo group, which was not a statistically significant difference.

There appeared to be no harmful effects on the fetus, a finding echoed in previous trials.

But this study had one surprise finding: more frequent premature rupture of membranes among women taking vitamins. "That was completely unexpected," said Spinnato, who is following up on the finding.

Other than the possibility that vitamin E is canceling out vitamin C, there is no clear explanation for why the combination didn't work.

"One of the continuing challenges to vitamin supplementation as a general thing is getting it from leafy vegetables is different than getting it from a pill," Spinnato said. "There are also those who argue that we didn't start [giving the vitamins] early enough, but that argument is difficult to swallow. There are medical and legal ramifications even for vitamins."

More information

To learn more about preeclampsia, visit the March of Dimes.

SOURCES: Joseph A. Spinnato II, M.D., professor, obstetrics and gynecology, University of Cincinnati College of Medicine; Miriam Greene, M.D., assistant professor, obstetrics and gynecology, New York University School of Medicine, New York City; December 2007 Obstetrics & Gynecology
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