November 23, 2006 — A new study by Mayo researchers suggests that women who develop hypertension during pregnancy face a higher risk for stroke, coronary heart disease, hypertension, and microalbuminuria later in life.
"Even though it's logical, it's common sense, that if someone becomes hypertensive during pregnancy, they are hypertensive later in life, there really are no data to support that," lead author Vesna D. Garovic, MD, from the Mayo Clinic in Rochester, Minnesota, told Medscape.
She presented their findings at the American Heart Association 2006 Scientific Sessions, in Chicago, Illinois, and subsequently at the American Society of Nephrology's 39th Annual Meeting and Scientific Exposition in San Diego, California.
"We thought it would be nice to show these results to both cardiologists and nephrologists, because it’s an area of interest for both specialties," Dr. Garovic, a nephrologist, noted.
History of Hypertension
Hypertension affects about 10% of pregnancies in the United States, the authors note. In this study, Dr. Garovic and colleagues aimed to assess whether women who develop hypertension during pregnancy are at higher risk for cardiovascular and renal outcomes.
To do this, they used data on 4782 women who had participated in the Family Blood Pressure Program (FBPP), all of whom were considered to have a higher risk for hypertension owing to family history, which was defined as belonging to sibships with 2 or more members who had hypertension diagnosed before age 60 years.
They were then categorized according to whether they had no history of pregnancy lasting more than 6 months (718), only normotensive pregnancies (3421), or at least 1 hypertensive pregnancy (643).
Frequently in young women, pregnancy is the first occasion that their blood pressure is checked, Dr. Garovic noted, and so a diagnosis of hypertension during pregnancy cannot rule out the possibility that the woman was hypertensive prior to that. "To differentiate between immediate complications of hypertensive pregnancy disorders and those later in life, all of the analyses for cardiovascular outcomes in hypertension were done after the age of 40, assuming that pregnancy would have happened earlier," she noted.
Despite their fairly young age, a median of 54 years in this cohort, women who were diagnosed with hypertension during pregnancy had a significantly higher risk for stroke, coronary heart disease (CHD) events, and subsequent hypertension after the age of 40 than those who had had only normotensive pregnancies. They also had a higher urine albumin-creatinine ratio (UACR), and a higher body-mass index (BMI) than women with normotensive pregnancies.
Events Later in Life Among Women With a History of Hypertension in Pregnancy vs Normotensive Pregnancy
|
Endpoint
|
Normotensive Pregnancy (%)
|
Hypertensive Pregnancy (%)
|
P
|
|
Stroke
|
2.7
|
5.2
|
.003
|
|
CHD
|
5.4
|
6.8
|
.049
|
|
Hypertension
|
56.9
|
60.6
|
< .001
|
|
UACR > 30
|
11.7
|
16.8
|
.003
|
Interestingly, women with normotensive pregnancies had lower creatinine levels than those who had never had a pregnancy lasting longer than 6 months.
They also looked at the relationship between hypertension in pregnancy and novel risk factors, such as homocysteine and C-reactive protein (CRP), in a subset of 1755 women in the FBPP who participated in the Genetic Epidemiology Network of Arteriopathy (GENOA). Women with a history of hypertensive pregnancy had higher CRP and homocysteine levels, both when BMI was included in the multiple regression models and when it was not. No difference was seen in levels of lipoprotein (a) or small dense LDL cholesterol between groups.
Chicken or Egg?
It's not clear at this point whether this relationship can be explained simply by the fact that risk factors for hypertensive disorders (including preeclampsia), such as higher BMI, diabetes, and kidney disease, are the same as those for cardiovascular disease, she said.
A competing theory is that hypertensive pregnancy disorders induce vascular and metabolic changes that modify a woman's overall risk profile for these events later in life, Dr. Garovic said. Preclinical studies, for example, have shown that animals with high levels of angiotensin 2, when given a high-salt diet, will develop hypertension. "Pregnancy is a high angiotensin 2 state," she pointed out, "so these hormonal changes that occur during pregnancy, specifically those relative to blood-pressure control, may somehow be modified in a way that changes the overall risk profile. It's a very intriguing hypothesis and I think we are going to start seeing more and more research in this area."
More immediately, in practice, Dr. Garovic now asks about pregnancy outcomes when taking a history and assessing risk factors in her patients. "If someone has had 1 or 2 hypertensive pregnancies, these are women who should be advised to check their blood pressure on a regular basis, work on their diets, on their lipid profile, on their exercise regimen, and on lifestyle modifications that can improve overall risk profiles and may affect longtime outcomes."
AHA 2006 Scientific Sessions: Abstract 2025.
Renal Week 2006: ASN Annual Meeting: Abstract TH-FC050.
Medscape Medical News © 2006 Medscape
Cite this: Susan Jeffrey. Hypertension in Pregnancy Linked to Increased Risk for CVD, Microalbuminuria - Medscape - Nov 23, 2006.
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