Hypertensive Disorders in Pregnancy Tied to Future Atrial Fibrillation

Women who develop hypertensive disorders of pregnancy (HDP) when pregnant with their first baby are more likely to later be diagnosed with atrial fibrillation (AF) and face an increase in premature mortality, according to an observational analysis of Canadian data.

The conditions span a broad swath of severity—from gestational hypertension to chronic hypertension in pregnancy, preeclampsia, or a mix of both chronic hypertension and preeclampsia. The new study, led by Amy Johnston, PhD (University of Ottawa, Canada), found a dose-response relationship, with more severe HDPs carrying the greatest risks.

“Up to this point, there has been really robust evidence . . . demonstrating that having a hypertensive disorder of pregnancy significantly increases a woman’s future risk of a number of different cardiovascular events,” said Thais Coutinho, MD (Mayo Clinic, Rochester, MN), who served as senior author of the new study along with Jodi D. Edwards, PhD (University of Ottawa). This research, Coutinho told TCTMD, has touched on endpoints as diverse as heart failure, myocardial infarction, and both all-cause and CV death.

What hasn’t been looked at in depth, however, is the link between HDPs and atrial fibrillation, which is known to be more common, in general, among people with hypertension. This is an especially important question because AF is becoming the “cardiovascular epidemic of our generation,” she said. The paper notes that the global prevalence of the arrhythmia has doubled over the past 30 years, reaching 38 million people in 2017.

As reported by TCTMD, it’s become increasingly clear that adverse pregnancy outcomes, including hypertensive disorders and others, are linked to an uptick in cardiovascular disease later in life. Some of these associations can be traced to genetics, though it’s also possible that these complications in pregnancy themselves give rise to subsequent CV events and early death. Importantly, though, research also suggests it’s possible to curtail some of that added risk through lifestyle changes and risk factor management.

The new paper was published earlier this month in Circulation as part of the journal’s annual Go Red for Women issue.

Coutinho said their findings didn’t come as a surprise, given prior data on other forms of CVD. “It makes sense that A-fib is also part of that group now,” she commented. What was unexpected, she added, is how rapidly the adverse pregnancy outcome made its mark on women’s lives: on average, just 7 years after giving birth.

Dose-Response Relationship

Using data housed at the Institute for Clinical Evaluative Sciences in Canada, Johnston and colleagues conducted a population-based retrospective cohort study including 771,521 women (median age 29 years) discharged after delivery of their first live or stillborn singleton infant between 2002 and 2017 in the province of Ontario.

Around 8% of these women were diagnosed with HDP during that 16-year span. During 7,380,204 person-years of follow-up, there were 2,483 diagnoses of incident AF and 2,951 deaths, translating to absolute rates of 0.3% and 0.4%, respectively. The median times to AF diagnosis or death each were around 7 years postpartum.

Having a history of any HDP was associated with increased risk of both incident AF and death without a prior AF diagnosis (adjusted cause-specific HRs of 1.45; 95% CI 1.28-1.64 and 1.31; 95% CI 1.15-1.47). Moreover, a dose-response pattern was seen, such that more severe subtypes of HDP as well as chronic hypertension before pregnancy led to 1.5- to 2.2-fold increases in AF and 1.4- to 2.1-fold increases in death compared with no hypertension during pregnancy.

We cannot just let these women disappear from the healthcare system. Thais Coutinho

“These findings underscore the need to consider HDP history in risk calculation/stratification for arrhythmic and nonarrhythmic cardiovascular diseases, improve surveillance of traditional and female-specific cardiovascular disease risk factors, and develop targeted prevention strategies to reduce the occurrence and burden of HDP,” the researchers conclude.

Coutinho cautioned, though, that it’s necessary to keep the data in perspective. While the relative increase in risk is noteworthy, “you have to also pay attention to the absolute rates of A-fib and death,” she stressed. “These are less than a half a percent, right? So the reality here is that the majority of women in general that are having babies, they’re going to be just fine.”

Given the low absolute rate of AF they found, it may not make sense to screen for the condition in all women who previously had HDP, said Coutinho. “If you just start to monitor every single one of these people, and most of them will not develop A-fib, is that a good deployment of healthcare resources?”  

She said the next steps will be to see if it’s possible to identify, among pregnant women, the individuals who are predisposed to HDP and subsequent arrhythmias.

 Already, “there’s so much data to support increased cardiovascular risk” in women with adverse pregnancy outcomes, Coutinho pointed out. “However, patients don’t know it. Healthcare providers don’t know it. . . . [It’s necessary] to understand there is a risk here and that we cannot just let these women disappear from the healthcare system.”