High blood pressure in pregnancy increases risk of heart disease: Study

Women who develop high blood pressure during pregnancy may be more likely to experience it again later or be diagnosed with other risk factors for heart disease like high cholesterol or diabetes, a U.S. study suggests.

Preeclampsia and gestational hypertension are two forms of high blood pressure that commonly develop during pregnancy. While previous research has linked these pregnancy conditions to an increased risk of heart attack and stroke later in life, the current findings offer fresh insight into which women may be at risk.

For the study, researchers examined data on almost 59,000 women who gave birth for the first time between 1964 and 2008, at an average age of 27. Overall, 2.9 percent of them developed gestational hypertension and 6.3 percent developed preeclampsia, the more severe form of high blood pressure during pregnancy.

Compared with women who had normal blood pressure throughout their first pregnancy, women who developed gestational hypertension were almost three times more likely to have high blood pressure again in the future, while women with preeclampsia had more than double the risk.

Gestational hypertension was also associated with a 65 percent higher likelihood that women would develop diabetes, and a 36 percent higher risk of high cholesterol.

Preeclampsia, meanwhile, was associated with 75 percent greater chance that women would develop diabetes and a 31 percent increased risk of high cholesterol.

“It is important that these women tell their doctor about their preeclampsia or gestational hypertension history (because) it increases their risk for cardiovascular disease risk factors and events,” said lead study author Jennifer Stuart of the Harvard T.H. Chan School of Public Health and Brigham and Women’s Hospital in Boston.

“While doctors typically screen for these cardiovascular disease risk factors in older adults, we see that women with high blood pressure during pregnancy develop these risk factors earlier in life than women with normal blood pressure in pregnancy,” Stuart added by email. “Therefore, it is especially important for these women to regularly see their doctor after pregnancy to monitor their blood pressure, glucose, and cholesterol.”

For women with gestational hypertension or preeclampsia, the risk of developing high blood pressure, diabetes or elevated cholesterol was highest in the first years after they gave birth, researchers report in the Annals of Internal Medicine.

Other risk factors for heart attack and stroke like obesity, smoking and a family history of heart disease didn’t appear to influence whether women with preeclampsia or gestational hypertension developed risk factors for heart disease after pregnancy, researchers found.

The study wasn’t a controlled experiment designed to prove whether or how elevated blood pressure during pregnancy might directly cause heart problems in the future. And the study looked at risk factors for heart disease, not actual cardiovascular events like heart attacks or strokes.

Researchers also relied on survey participants to accurately recall and report any diagnosis of high blood pressure during pregnancy, and their recollections might not always be accurate. Another limitation is that all of the participants were nurses, and it’s possible results might look different for women with different career paths.

Even so, the results offer fresh evidence that women who develop high blood pressure in pregnancy may have a greater risk for heart disease at an earlier age than their peers who don’t experience preeclampsia or gestational hypertension, Dr. Abigail Fraser, author of an accompanying editorial and a researcher at the University of Bristol in the UK.

“This has potential implications for care,” Fraser said by email. “Women with a history of hypertension during pregnancy should potentially have their blood pressure, glucose and cholesterol levels checked at regular intervals and at an earlier age.”

While scientists aren’t certain what causes preeclampsia or how the condition might make women more likely to develop risk factors for heart disease in the future, there are still steps women can take to prevent heart disease.

High blood pressure in pregnancy and afterwards, as well as diabetes and high cholesterol, are more likely when women are obese, Fraser noted. “Therefore, maintaining a healthy weight throughout life - before pregnancy and after - is important,” Fraser advised.