Taking vitamins was once thought to reduce a woman's odds for developing preeclampsia and other conditions. But vitamins C and E in particular may not help reduce that risk after all.
A number of small research studies over the past decade led to hope that preventing preeclampsia during pregnancy could be as easy as taking a few extra vitamin supplements. But in the largest study of vitamins and preeclampsia prevention to date, researchers from the University of Pittsburgh have found that antioxidant vitamins C and E show little or no effect on lowering a woman's risk for developing preeclampsia, high blood pressure, and other hypertension-related complications.
Published April 8, 2010 in the New England Journal of Medicine, the study of over 10,000 pregnant women tracked participants' health from the late first trimester or early second trimester through delivery. In addition to their normal prenatal vitamins, half of the women in the study received 1,000 milligrams of vitamin C and 400 international units of vitamin E daily (about 10 times the normal daily dose). The other 5,000 women received a placebo.
According to researchers, approximately 7.2 percent of women taking the extra vitamins developed preeclampsia, compared with 6.7 percent among those taking a placebo. When it came to hypertension and other blood pressure-related complications, 6.1 percent of moms-to-be taking C and E supplements encountered problems, compared with 5.7 percent of women taking the placebo.
"These results are very useful," says Dr. Catherine Y. Spong of the National Institute of Child Health and Human Development in a L.A. Times piece on the study. "In this case, it shows us that what originally appeared to be a promising treatment did not actually offer any benefit clinically."
Preeclampsia, a sudden increase in blood pressure accompanied by swelling and protein in the urine, usually occurs after the 20th week of pregnancy. If left untreated, the complication may damage a mother's kidney, liver, and brain and often leads to the early delivery and preterm birth.
Preeclampsia affects up to 6 percent of all pregnancies. According to the March of Dimes, women can take steps to lower their risk for preeclampsia by reaching a healthy weight before becoming pregnant and not smoking during pregnancy. Women who do have hypertension should see their healthcare provider before trying to get pregnant—some high blood pressure medication should not be used during pregnancy (your doctor can provide an alternative).