A study from Brigham and Women's Hospital and the Harvard T.H. Chan School of Public Health finds an interesting link between high blood pressure in pregnancy and cardiovascular risk factors later in life.
Preeclampsia and gestational hypertension are common pregnancy complications, according to the CDC. These complications can alert women and healthcare providers to risks involving their future cardiovascular health, according to a new study.
Women with a history of preeclampsia or gestational hypertension in pregnancy had a two- to three-fold-200% to 300%-higher risk of developing chronic hypertension, a 70% higher risk of diabetes, and a 30% higher risk of high cholesterol than women who had normal blood pressure in pregnancy, according to the study, published in Annals of Internal Medicine on July 3, 2018.
These relationships persisted even after accounting for pre-pregnancy shared risk factors like body mass index, smoking, and family history, the study shows.
Jennifer Stuart, ScD, postdoctoral research fellow at Brigham and Women’s Hospital and the Harvard T.H. Chan School of Public Health, and colleagues studied more than 58,000 women enrolled in the large prospective cohort study the Nurses’ Health Study II (NHS II) who did not have cardiovascular disease or risk factors at the time of enrollment and had given birth at least once. Women were followed for self-reported physician diagnosed chronic hypertension and high cholesterol and confirmed type 2 diabetes from their first birth through 2013 with a mean follow up of 25 to 32 years.
“Previous studies have shown that women with a history of a high blood pressure in pregnancy are more likely to develop cardiovascular disease events like heart attack and stroke later in life when compared to women with normal blood pressure in pregnancy,” Stuart says. “However, what is less clear is to what extent these women are more likely to develop chronic hypertension, diabetes, and high cholesterol and when these risk factors begin to emerge after pregnancy.”
Studies on the relationship between high blood pressure in pregnancy and cardiovascular disease risk factors after pregnancy have shown increased risks for chronic hypertension and type 2 diabetes among women with a history of high blood pressure in pregnancy with less consistent associations for high cholesterol, according to Stuart.
“However, these previous studies have been limited by small numbers, short follow-up, or a lack of information on shared risk factors that may increase the risk for both the high blood pressure in pregnancy and the cardiovascular disease risk factors later in life,” she says. “Our study, conducted in the Nurses’ Health Study II, is one of the largest studies with one of the longest lengths of follow-up and provides the most complete control for shared risk factors, including pre-pregnancy body mass index, smoking, diet, and family history. With follow-up ranging from two to 50 years after first pregnancy, this study advances our understanding of the trajectory of cardiovascular disease risk after a hypertensive pregnancy.”
Improving cardiovascular health for the 10% to 15% of women who have given birth that have a history of preeclampsia or gestational hypertension requires coordination across care providers and across the life course, according to Stuart.
“Healthcare executives have the potential to be valuable partners in improving the communication of risk and provision of care across specialties, including obstetrics, primary care, and cardiology,” she says. “Since women are typically diagnosed with high blood pressure in pregnancy by their obstetrician, it is important that this information be passed on to their primary care doctor after pregnancy.”
In addition to being at increased risk for chronic hypertension, diabetes, and high cholesterol, the researchers also found that these cardiovascular disease risk factors developed at an earlier age and sooner after pregnancy in women with high blood pressure in pregnancy when compared to women with normal blood pressure in pregnancy.
“Our data showed that the increased risk emerges shortly after pregnancy, particularly for chronic hypertension and high cholesterol,” Stuart says. “We also found that if a woman has had high blood pressure in more than one pregnancy, her risk for these cardiovascular disease risk factors is even higher.”
The take-home message for women is that if they have had preeclampsia or gestational hypertension, they are at an increased risk for high blood pressure, diabetes, and high cholesterol after pregnancy, according to Stuart.
“After having high blood pressure in pregnancy, these women should maintain a heart healthy diet and lifestyle and see their doctor for screening she says. “Previous research by our group has shown that achieving and maintaining a healthy body mass index is especially important for women with a history of high blood pressure in pregnancy.”
The findings also suggest that prevention and screening strategies for these cardiovascular disease risk factors should be developed and evaluated for women with a history of preeclampsia or gestational hypertension.
The American Heart Association (AHA) includes preeclampsia and gestational hypertension on its list of risk factors for heart disease and stroke.
As recommended by the AHA, doctors should obtain a detailed history of pregnancy complications being sure to capture information on preeclampsia and gestational hypertension, Stuart says. “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. Therefore, it is especially important for these women to regularly see their doctor after pregnancy to monitor their blood pressure, glucose, and cholesterol,” she says