Study Highlights List of Risk Factors for Preeclampsia

Researchers have pinpointed the factors that increase a woman’s risk of developing the common pregnancy problem called preeclampsia (search).

Preeclampsia is marked by three specific symptoms: water retention (with swelling particularly in the feet, legs, and hands); high blood pressure; and protein in the urine, a sign of possible kidney damage. All three must be present at the same time.

Symptoms can include swelling, sudden weight gain, persistent headache, vision changes, and vomiting. But some women experience no symptoms at all. Preeclampsia usually appears after 20 weeks of pregnancy.

The only real cure is the birth of the baby. If the baby is not ready to be delivered, bed rest or medication can be used to help allow the baby more time to develop. If left untreated, preeclampsia can develop into eclampsia (search), a dangerous condition that can cause seizures and coma in the mother and death in the mother and baby.

The review by researchers from Oxford, England’s John Radcliffe Hospital is one of the first to attempt to quantify risk factors for preeclampsia, a condition that complicates as many as one in eight pregnancies and is a leading cause of maternal and infant death and premature birth.

Women who have had preeclampsia before have a sevenfold higher risk for developing the potentially life-threatening condition in subsequent pregnancies.

“These findings show the importance of following pregnant women closely if they have had preeclampsia in the past,” lead researcher Kirsten Duckitt, MD, tells WebMD.

“The thinking has been that this is not such a big concern and that women with a previous preeclampsia will be fine. But it is clear that these women need to be watched closely.”

Watch Out for the Signs

In addition to having had preeclampsia before, the researchers found that several other factors increase the risk of developing preeclampsia.

—Women with diabetes are four times as likely to develop preeclampsia.

—Giving birth for the first time triples the risk.

—Carrying more than one child is associated with about a threefold increase in risk.

—A family history of preeclampsia was found to nearly triple the risk.

—Becoming pregnant after age 40 nearly doubled a woman’s risk.

—Having high blood pressure prior to pregnancy slightly elevated the risk of developing preeclampsia.

—Being overweight more than doubled risk of preeclampsia.

Antiphospholipid syndrome (search), in which women have abnormal antibodies, increased the risk of preeclampsia almost tenfold. The condition has also been linked to an increased risk for miscarriage.

“Clinicians have long known about these risk factors, but I think the strength of some of these associations will surprise some people,” University of Glasgow, Scotland, obstetrics and gynecology professor Ian A. Greer, MD, tells WebMD.

In the new review, published in the March 12 issue of the British Journal of Medicine, Duckitt and colleague Deborah Harrington reviewed 52 preeclampsia studies conducted between 1966 and 2002.

Know Your Risk

In an editorial accompanying the study, Greer wrote that much more could be done to identify pregnant women at risk for preeclampsia.

“Why have we failed when the identification of women at risk, and the diagnosis of preeclampsia through the measurement of blood pressure and urine, is arguably the most important aspect of a regular (prenatal) assessment?” he writes.

Fiona Milne of the U.K. group Action on Preeclampsia tells WebMD that all pregnant women need to know their individual risk factors for preeclampsia, see their doctors often, and make sure their blood pressure and urine are checked during every office visit.

“We know that this condition develops from diagnosis to the point where a woman could potentially die within an average of about two weeks,” Milne says. “Preeclampsia can be identified with a simple check of blood pressure and urine analysis. This isn’t rocket science.”

Texas ob-gyn Susan M. Ramin, MD, tells WebMD that doctors in the U.S. tend to do a good job of identifying preeclampsia in their patients. Ramin directs the division of maternal and fetal medicine at the University of Texas Science Center at Houston.

“If a woman is getting regular prenatal care she will have her weight and blood pressure and urine checked regularly,” she says. “We know what the risks are. The problem is that we don’t have good treatments unless a woman is at term and can deliver.”

Ramin is involved in a National Institutes of Health-funded study to determine whether the antioxidant vitamins C and E can protect women against preeclampsia. Roughly 10,000 women who are giving birth to their first babies will be enrolled in the trial.

By Salynn Boyles, reviewed by Michael W. Smith, MD

SOURCES: Duckitt, K. and Milne, F. British Medical Journal, March 12, 2005; vol 330: pp 576-580 and 565-567. Kirsten Duckitt, MD, department of obstetrics and gynecology, John Radcliffe Hospital, Oxford, England. Fiona Milne, guideline coordinator, Action on Preeclampsia, Middlesex, England. Ian Greer, MD, professor of obstetrics and gynecology, University of Glasgow, Scotland. Susan M. Ramin, MD, director, division of maternal and fetal medicine, University of Texas Health Science Center, Houston.