FRIDAY, Nov. 17, 2006 (HealthDay News) -- Women who experience high blood pressure during pregnancy have a higher risk of stroke, heart and kidney disease later in life, a new study found.
The study calls into question the commonly held belief that high blood pressure during pregnancy is a fleeting problem with no adverse effects on later health, said Dr. Vesna Garovic, lead author of the report and an assistant professor of internal medicine at the Mayo Clinic in Rochester, Minn.
The study, which included nearly 5,000 women, isn't the first to report the association, Garovic said. "But this is the largest study and the first study to include multiracial subjects," she said.
"High blood pressure in pregnancy appears to be an under-recognized risk factor for cardiovascular disease later in life," Garovic said. About 10 percent of pregnancies are affected by high blood pressure, she said.
The study findings were presented Thursday at the American Society of Nephrology's annual meeting, in San Diego.
Garovic and her colleagues analyzed data from 4,782 women who all had a high family risk of high blood pressure and were participating in the National Heart, Lung, and Blood Institute Family Blood Pressure Program study from 2000 to 2005. The average age of the women when the data was analyzed was 54. They reported their own health conditions.
The researchers looked at three groups: 718 women who had no history of a pregnancy lasting more than six months; 3,421 women who had normal blood pressure throughout their pregnancies; and 643 women who had hypertension during pregnancy. Women were white, black, Hispanic and Japanese. Most had a brother or sister with high blood pressure.
Women who had high blood pressure during pregnancy had twice the risk of stroke as those who had normal pressure during pregnancy. They also had 1.5 times the risk of heart attack and 1.5 times the risk of developing high blood pressure after age 40, the researchers found.
Those who suffered from high blood pressure during pregnancy were also more likely to have small amounts of the protein albumin in their urine, which is an early sign of kidney disease, Garovic said.
High blood pressure is common as people get older, but the study authors found it struck earlier in women who had experienced the condition during pregnancy. "In women with a history of hypertension in pregnancy, 50 percent of them had high blood pressure by age 52," Garovic said. "In women with normal tension pregnancies, 50 percent of them had high blood pressure by age 60."
The findings of this study, as well as other recent research that came to the same conclusions, fly in the face of conventional thinking, Garovic said. Her research and other recent studies suggest the effects of pregnancy-related high blood pressure are more long-lasting and serious than believed.
Exactly why the elevated blood pressure boosts risk later in life isn't known, but Garovic said the conditions may share risk factors such as obesity. The women with high blood pressure during pregnancy tended to be obese compared with the women who did not get it, the study found.
Or, the high blood pressure during pregnancy may induce long-term metabolic and blood vessels abnormalities, leading to cardiovascular problems later, she said.
Physicians should ask women about their blood pressure status during pregnancies during routine exams, Garovic said. And, if the doctors don't ask, women should volunteer the information so they can be followed appropriately.
"This research is monumental," said Dr. Nieca Goldberg, chief of women's cardiac care at Lenox Hill Hospital in New York City, and author of The Women's Healthy Heart Program. She was not involved in the study.
"It's going to set a new tone for us for evaluating risk factors for heart disease for women. What is really important about studies like this is, we are starting to look at women's health throughout their life cycle. For a long time, we thought conditions during pregnancy stayed there and had no effect on later life health."
To learn more about high blood pressure during pregnancy, visit the March of Dimes.