Extra Vitamin C and E Don't Prevent Preeclampsia

High doses didn't lower rates of pregnancy complication in low-risk women

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By Serena Gordon
HealthDay Reporter

WEDNESDAY, April 26, 2006 (HealthDay News) -- New research suggests that taking large doses of vitamins C and E won't prevent preeclampsia, a relatively common but potentially dangerous pregnancy complication.

In a study of nearly 2,000 women pregnant for the first time, researchers found that the addition of these antioxidant vitamins didn't decrease the rate of preeclampsia or lower the risk of complications for infants of women with preeclampsia.

"Our study found that for women in the first pregnancy, taking vitamin C and E supplements did not reduce the risk of developing preeclampsia," said study author Alice Rumbold, a postdoctoral research fellow at the University of Adelaide and Women's and Children's Hospital in North Adelaide, Australia.

"However, there was nothing in the results to suggest that the vitamin C and E supplements were harmful to the baby," she added.

Results of the study appear in the April 27 issue of the New England Journal of Medicine.

About 5 percent of all pregnant women in the United States develop preeclampsia, according to the March of Dimes. The first signs are usually high blood pressure and protein in the urine. 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.

The current study included 1,877 Australian women who were pregnant for the first time. The researchers excluded women who were pregnant with multiple fetuses and women with chronic health conditions, such as kidney disease and high blood pressure.

Nine hundred and thirty-five women were randomly assigned to receive vitamin therapy and 942 were given a placebo. The vitamin therapy consisted of 1,000 milligrams of vitamin C and 400 international units of vitamin E daily, beginning in the second trimester and continuing until delivery.

The researchers found no statistically significant differences between the two groups. Six percent of the vitamin group developed preeclampsia vs. 5 percent of the placebo group. Rates of death or serious outcomes for the infants were 9.5 percent in the vitamin group and 12.1 percent for the placebo group. The risk of having a low birth weight (below the 10th percentile) baby was 8.7 percent for those receiving vitamin therapy and 9.9 percent for those on placebo.

"This trial addresses the low-risk group of women and vitamin supplementation showed no apparent benefit in reducing the rate of preeclampsia or poor infant outcomes," said Dr. Arun Jeyabalan, an assistant professor in the division of maternal fetal medicine at Magee Women's Hospital at the University of Pittsburgh.

But, she added, "A couple of questions still remain open in my mind." She pointed out that this study was done on Australian women, and that the results in a different population, such as U.S. women, might be different. Also, a larger group of women would provide a more statistically definitive answer regarding the potential benefits or risks of vitamin C and E supplementation.

Dr. Abdulla Al-Khan, director of Perinatal Diagnostics and Therapeutics in the department of Obstetrics, Gynecology and Women's Health at Hackensack University Medical Center, N.J., said he would have liked to have seen this study conducted on women who were already at risk for preeclampsia.

"The risk of preeclampsia is definitely less for those women that they included than for those they excluded. It's not surprising that there is no difference in outcome when you look at a low-risk population," said Al-Khan. "If you target really high-risk patients, maybe then you can get an answer."

Both Jeyabalan and Al-Khan said there's currently not much women can do to prevent preeclampsia. Al-Khan recommended eating a healthy diet full of vitamins and minerals, getting a moderate amount of exercise and reducing your stress levels.

When it came to vitamin supplements, Jeyabalan had this advice: "This is a treatment that at least for now has no clear benefit and women should not take this therapy without being in a trial situation or without careful consultation with their physician."

Additionally, she pointed out that the levels of vitamins used in this study far exceeded those contained in prenatal vitamins. "Any supplementation above and beyond prenatal vitamins should be discussed with your obstetrician," she advised.

More information

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

SOURCES: Alice Rumbold, Ph.D., postdoctoral research fellow, University of Adelaide, Women's and Children's Hospital, North Adelaide, Australia; Arun Jeyabalan, M.D., assistant professor, division of maternal fetal medicine, department of Obstetrics, Gynecology and Reproductive Sciences, Magee Womens Hospital, University of Pittsburgh, Pa.; Abdulla Al-Khan, M.D., assistant professor and director, Perinatal Diagnostics and Therapeutics, department of Obstetrics, Gynecology and Women's Health, Hackensack University Medical Center, Hackensack, N.J.; April 27, 2006, New England Journal of Medicine

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