The brothers of women who have hypertension during pregnancy may face increased risks of hypertension and heart disease in later life, according to the study.
"We wanted to isolate the effect of high blood pressure during pregnancy by comparing the risk of hypertension, heart disease, and stroke in women who had hypertension during pregnancy, and their sisters," says study author Dr. Vesna Garovic, of the Mayo Clinic.
"We also wanted to determine whether heart disease risk was increased in brothers and sisters of women who had hypertension in pregnancy."
Experts estimate that hypertension develops in around 8% of all pregnancies. There are different types of hypertension that can occur during pregnancy. Gestational hypertension, for example, is high blood pressure that develops after 20 weeks of pregnancy.
Hypertension during pregnancy is a recognized risk factor for future hypertension and cardiovascular disease. According to the researchers, this could be due to a predisposition that runs in families, or it could reflect damage caused by high blood pressure during pregnancy.
To isolate the effect of hypertension during pregnancy, Dr. Garovic and colleagues analyzed a total of 954 groups of siblings (919 men and 1,477 women) that took part in the Genetic Epidemiology Network of Arteriopathy (GENOA) study - a prospective study of hypertension among siblings that ran from 1995-2005. Each group of siblings (sibships) included at least one woman who had given birth.
Familial factors 'may contribute to increased risk of future hypertension'
Women who had hypertension during pregnancy were 75% more likely to develop hypertension later in life than sisters with normal blood pressure levels.
- Around 1 in every 3 American adults have high blood pressure
- Only around 52% of people with high blood pressure have the condition under control
- Hypertension increases the risk of heart attack, stroke and kidney disease.
The siblings of women who had hypertension during pregnancy were more likely to develop hypertension themselves in later life than those whose sisters had not had hypertension during pregnancy, with male siblings 24% more likely and female siblings 15% more likely.
Perhaps most interesting, however, was the discovery that while the male siblings of women who had hypertension during pregnancy were at an increased risk of cardiovascular disease later in life, female siblings were not.
"These results suggest familial factors contribute to the increased risk of future hypertension in women who had hypertension in pregnancy," the authors write. "Further studies are needed to clarify the potential role of non-familial factors. Furthermore, a sibling history of hypertension in pregnancy may be a novel familial risk factor for future hypertension."
They also state that their findings should be interpreted with caution, as the study was both small and focused on families with a high prevalence of hypertension or diabetes. As a result, further studies should be population based to determine whether these findings also occur in the general population.
Recently, Medical News Today reported on a study suggesting that beta blockers - a form of medication typically used to treat hypertension - could also have anticancer properties warranting further investigation.
The authors of the study, published in Cancer, found that the use of beta blockers in women with ovarian cancer was linked to longer overall survival from the disease.