March 10, 2000 (Eugene, Ore.) -- Despite recent research suggesting that antioxidants might play a role in preventing preeclampsia, experts say that pregnant women shouldn't start taking megadoses of vitamins C and E in hopes of warding off the condition. Preeclampsia is one of the major causes of premature births and of deaths and illness in pregnant women and their babies.
"We have no idea whether high-dose antioxidants are safe for the baby," says James M. Roberts, MD. "They probably are, but this really needs to be tested in a controlled setting first." Roberts is professor and vice chairman for research in the departments of obstetrics, gynecology and reproductive disease, director of the Magee-Womens Research Institute, and L.C. Hilliard Hillman chairman of women's and infants' health research at the University of Pittsburgh. Women should consult their doctors before taking vitamins in doses exceeding those of prenatal vitamins.
Roberts is an expert in complicated pregnancies. His extensive review of what is known and not known about preeclampsia was published in the February issue of Seminars in Perinatology.
Women with preeclampsia experience a sudden rise in blood pressure, too much weight gain, severe headaches, visual disturbances, protein in their urine, and a buildup of fluids in their tissues. Because some of these symptoms can occur in normal pregnancy, it takes evaluation by a physician to confirm that a woman has the condition. Prompt diagnosis and treatment are important because not only can women with preeclampsia get very sick, but their fetuses can grow poorly. Many infants are delivered prematurely when the mother's condition worsens.
Though preeclampsia's cause is unknown, experts speculate that some of its effects are due to an abnormal implantation of the placenta into the uterine wall and inadequate blood flow between the uterus, placenta, and fetus.
Many recent studies suggest that an inadequate placental blood supply starts a process called oxidative stress, which results in problems throughout the mother's blood vessels.
"If this theory is correct, and oxidative stress in fact is responsible for the disease, then there is a good chance you could prevent it by using antioxidant therapy, such as vitamins C and E," Roberts says. One small English study reported a decline in cases of the disease in women who used this therapy.
"This is very interesting, because it looks like this really could be effective," Roberts says. "The bad news is, at this point only 70 babies have actually been exposed to this therapy."
Because of that study, a magazine for parents recently published an article urging pregnant women to take extra vitamin C and E to prevent preeclampsia, Roberts says. "That is scary to many of us who are researching this issue. We're concerned that women may start to use these substances before the appropriate studies have been done. There may turn out to be problems we don't know about."
Les Myatt, MD, agrees with Roberts. "The problem is that people may seize on this and adopt it too early. The English study was a small study that had significant results; now it needs to be repeated in larger numbers of women, and in different groups of women. We don't know yet if there may be harmful effects for the baby and/or mothers." Myatt is professor of obstetrics and gynecology at the University of Cincinnati School of Medicine.
"The best advice we can give any pregnant woman is to see her obstetrician early and regularly," Myatt says.