Pregnancy’s 'cardiovascular stress test' could trigger future chronic hypertension, research suggests.
Women with hypertensive disorders of pregnancy have seven times the risk of developing chronic hypertension in the following two years.
These enduring risks suggest women need to be monitored for a much longer duration, and more thoroughly, than they currently are, say experts.
The 13-year study of almost 120,000 pregnancies and deliveries found that the risk of a chronic hypertension diagnosis in the 24 months postpartum was 9.7% among women who had hypertensive disorders during pregnancy, compared to 1.5% of women who didn’t.
“These associations between hypertensive disorders of pregnancy and cardiovascular disease persisted even in the population with no pre-existing chronic hypertension,” the US researchers wrote in the American Journal of Obstetrics and Gynecology.
Women with hypertensive disorders of pregnancy – including gestational hypertension, preeclampsia, superimposed preeclampsia or eclampsia – also had three times the risk of heart failure within two years, (0.3% compared to 0.1%).
In addition, the risk of cardiomyopathy was tripled among those women with hypertensive disorders in pregnancy (0.6% compared to 0.2% in those without hypertension), the risk of severe cardiac disease more than doubled (1.6% compared to 0.7%) and the risk of cerebrovascular disease was 1.4 times higher within two years.
However, the US researchers did not find any association between hypertensive disorders of pregnancy and ischaemic heart disease or cardiac arrest/arrhythmia.
The risk of incident chronic hypertension didn’t taper off over time either – it stayed steady across the 24 months postpartum.
“This suggests that care specific to pregnancy complications should not be confined to the traditional 42-day postpartum period.”
The researchers said tailoring postpartum screening and interventions could reduce the risk of developing these cardiovascular conditions.
“Screenings could include a comprehensive history and physical exam, serum testing with cholesterol evaluation, diabetes evaluation, and possibly brain natriuretic peptide levels, cardiac imaging and cardiology referral.”
“Patients with hypertensive disorders of pregnancy may benefit from increased surveillance immediately postpartum and the use of a lower threshold for cardiac imaging and cardiology consultation,” they said.
Professor Jason Kovacic, executive director of the Victor Chang Cardiac Research Institute, said these “important findings” gave new insights into the long-term risk after delivery.
“It’s a significant step forward for the field in our understanding of hypertensive disorders of pregnancy, and what happens in the women after they deliver,” the practising cardiologist at Sydney’s St Vincent’s Hospital said.
The ongoing risk of hypertension warranted “increased vigilance well after pregnancy” in women with these hypertensive disorders of pregnancy, Professor Kovacic told TMR.
“They very clearly show that there’s significant increased risk of heart failure, cerebrovascular disease and stroke, cardiomyopathy, severe cardiac disease and new chronic hypertension.
Professor Kovacic said the findings helped prioritise risk.
“Clearly women that have hypertensive disorders of pregnancy need very careful follow-up, not just in a couple of weeks after pregnancy, but in the months after pregnancy so that any of these late-presenting disorders such as hypertension can be detected,” he said.
Professor Kovacic said it was important to manage the transition of care from obstetric care back to general practice for women with cardiovascular risk factors.
The researchers found that 36.5% of women that had a hypertensive disorder pregnancy had pre-existing chronic hypertension.
“But you can turn that around and say, well, 63.5% didn’t,” Professor Kovacic said.
“So there’s a significant number of women that didn’t have pre-existing problems in terms of hypertension, that subsequently did develop problems.
“We know that pregnancy is a form of stress test for the cardiovascular system and if you’re borderline or at risk for hypertension, then there’s added stress of having a pregnancy and all the body changes that go with that can bring out hypertension in some proportion of women.”
Professor Kovacic said while hypertension may resolve after delivery, weight gain and less exercise could lead to blood pressure and cholesterol “drifting up” again.
“It serves as an important signal for anyone that has these hypertensive disorders of pregnancy that there may be underlying risks that need to be worked through, or it may be that this is the first manifestation of hypertension.
“Women that have these disorders of pregnancy need particularly careful focus in the one-to-two-year period after pregnancy, as articulated by the study.”
Professor Kovacic said the study was a reminder to pay attention to the heart health of women.
“It underscores the real importance of heart health in women. Our society tends to think of heart disease as a problem of middle-aged men and this very clearly shows that it’s not just a disease of middle-aged men, and heart disease in all these different forms, including high blood pressure and heart failure and major cardiac events, is very much also a disease of women.”
American Journal of Obstetrics and Gynecology 2023, online 7 April
