Siblings of women who experience hypertension during pregnancy are at an increased risk of hypertension and cardiovascular events later in life, according to researchers.
Approximately 8% of women develop hypertension during pregnancy. These women are 1.5 to 2 times more likely to later develop hypertension and cardiovascular disease, and there is even greater risk in women who have developed early onset, recurrent, or superimposed preeclampsia. It is unclear, however, if the increased risk for cardiovascular events stems from the long-term damage of hypertension during pregnancy, or because these women have a family history of heart disease.
If the increased risk is due to a hypertensive pregnancy, then clinicians would have very little time to prevent or reverse the damage. However if the risk is increased by family history, then those individuals could benefit from early monitoring and access to preventive tools, suggested researcher Tracey Weissgerber, PhD, of the Mayo Clinic in Rochester, Minnesota, and colleagues.
Their study, published in the Journal of the American Society of Nephrology, revealed that women who developed hypertension during pregnancy were 75% more likely to develop hypertension again later in life than their sisters who had normal blood pressure during pregnancy.
The researchers examined more than 900 sibships from the Genetic Epidemiology Network of Arteriopathy (GENOA), a study investigating hypertension in white, black, and Hispanic individuals. Each sibship had at least two siblings who had hypertension before age 60 years, and at least one sibling who developed hypertension during pregnancy. The researchers excluded cases where women developed hypertension prior to or during the year of their first hypertensive pregnancy.
The results showed that women who had hypertension during pregnancy generally had higher body mass indexes (BMI) and were at a greater risk for diabetes than their sisters who were not hypertensive during pregnancy. They also developed hypertension at an earlier age than their sisters.
After adjusting for BMI and diabetes, the risk of coronary heart disease and stroke did not differ between women who had hypertension during pregnancy and their unaffected sisters.
Hypertension risk increased among the brothers and sisters of women who were hypertensive during pregnancy, which supports the claim that familial predisposition increases the risk for women to develop hypertension during pregnancy. This study suggests that researchers should examine sibling history of hypertension in pregnancy to determine if both men and women are at increased risk for additional chronic diseases. Population-based studies are needed to determine whether the results of this study apply to the general population.
In addition to increased risk for hypertension, brothers—but not sisters—of women who had hypertension during pregnancy may also have an increased risk for cardiovascular disease. The authors noted that, “this sex difference could suggest that while a sibling history of hypertension in pregnancy may provide information about future disease risk in men, a woman’s own pregnancy history is more informative than that of her sisters when predicting future disease risk.”
If implemented correctly, analyzing familial factors may shape future research to identify an individual’s risk for hypertension, as well as develop means of prevention and intervention for cardiovascular disease.