FRIDAY, Nov. 2 (HealthDay News) -- Women with cardiovascular risk markers are at heightened risk of developing preeclampsia when pregnant, and pregnant women who do develop preeclampsia are at higher risk for developing heart disease later, British and Norwegian researchers report.
Preeclampsia, a condition in which abnormally high blood pressure develops during the second half of pregnancy, affects about 5 percent of all first pregnancies and is dangerous for both mother and child, according to two studies published in the Nov. 2 online edition of the British Medical Journal.
In the first study, Norwegian researchers found that cardiovascular risk factors that show up before pregnancy increase the risk of preeclampsia sevenfold.
"This study is the first that confirms the hypothesis that lipid and blood pressure abnormalities before pregnancy are strong predictors of preeclampsia," said lead author Elisabeth Balstad Magnussen, a research fellow in the Department of Public Health Faculty of Medicine, Norwegian University of Science and Technology, Trondheim.
To assess the risk, the researchers looked at 3,494 women, recording any cardiovascular risk markers, including blood pressure, cholesterol, blood sugar levels, weight and body mass index, before pregnancy. Among the group, 133 developed preeclampsia during pregnancy, the researchers found.
Magnussen's team then found that those women who had high blood pressure, high cholesterol and high blood sugar levels before pregnancy were seven times more likely to develop preeclampsia compare with the others.
In addition, women who had a family history of high blood pressure, heart disease, or diabetes had double the risk of developing preeclampsia. And, being overweight or obese also increased the risk, the researchers found.
However, the research also showed that women who had used oral contraceptives had half the risk of preeclampsia compared with those who never used oral contraceptives.
"The findings suggest that preeclampsia and cardiovascular diseases may share a common origin, and that the increased risk of cardiovascular disease subsequent to preeclampsia, at least partly, is due to an underlying biological trait of the woman," Magnussen said.
In the second study, British researchers reviewed 25 studies that included 3.5 million women worldwide. Almost 200,000 had developed preeclampsia while pregnant. The researchers then calculated the future risk of heart disease, stroke, hypertension and thromboembolism.
"Women who have had preeclampsia are at a roughly twofold increased risk of cardiovascular disease in later life, compared with women who did not have preeclampsia," said lead researcher David Williams, a consultant obstetric physician at the Institute for Women's Health at Elizabeth Garrett Anderson Obstetric Hospital, University College London.
"Specifically, these women have an almost fourfold increased risk of hypertension, and a doubling of the risk of heart disease, stroke, and venous thromboembolism," he added.
Some of the larger studies in the review suggested that this increased risk of heart disease after preeclampsia is independent of other recognized risk factors and, therefore, should become an important factor when assessing a woman's cardiovascular risk, Williams said.
The risk of a cardiovascular disease usually increases with age, the researchers noted. The normal risk for heart disease among women 50 to 59, is about 8 percent, but for women who have a history of preeclampsia, it is 17 percent. At ages 60 to 69, the risk is 14 percent and 30 percent, respectively, Williams' team explained
In their analysis, the researchers didn't find any increased risk of cancer, including breast cancer. This suggests that there is a specific relationship between preeclampsia and heart disease, the researchers said.
One expert agreed with the conclusions of both studies.
"I believe in these findings that preeclampsia is related to cardiovascular disease," said Dr. Richard Levine, a senior investigator at the U.S. National Institute of Child Health and Human Development. "In women who develop preeclampsia, there are already signs of metabolic syndrome, which is linked to subsequent cardiovascular disease," he said.
Women who develop preeclampsia should be screened for heart disease, diabetes and metabolic syndrome, and women at risk for preeclampsia before becoming pregnant should also try to reduce their cardiovascular risk factors to help prevent the condition, Levine said.
"Get your weight under control," Levine said. "If you have diabetes or chronic hypertension, get that attended to and take medications to lower your cholesterol, exercise, and eat well."
For more on preeclampsia, visit the U.S. National Library of Medicine.
SOURCES: David Williams, Ph.D., consultant obstetric physician, Institute for Women's Health, Elizabeth Garrett Anderson Obstetric Hospital, University College London, U.K.; Elisabeth Balstad Magnussen, research fellow, Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Richard Levine, M.D., M.P.H., senior investigator, U.S. National Institute of Child Health and Human Development, Rockville, Md.; Nov. 2, 2007, online edition, British Medical Journal