Pregnancy Confers Unique Risk of Cardiovascular Disease, Two New Studies Suggest

Looking at preterm deliveries and multiple pregnancies may help clinicians risk stratify their patients later in life, according to investigators.

Pregnancy Confers Unique Risk of Cardiovascular Disease, Two New Studies Suggest

Several aspects of pregnancy seem to play roles in the likelihood of a woman developing heart disease, according to two studies published online today in the inaugural Go Red for Women issue of Circulation.

“Thirteen years ago, when the Go Red for Women initiative was launched, the landscape was much different than it is today,” write journal editors Sharon Reimold, MD, and Joseph Hill, MD, PhD (University of Texas Southwestern Medical Center, Dallas), in an editorial. “The role of implicit, gender-based bias in influencing our care of patients was not emphasized in the literature,” they say, adding that women have been historically underrepresented in research studies.

In the first paper, Jorge Wong, MD, MPH (McMaster University, Hamilton, Canada), and colleagues followed more than 34,000 participants from the Women’s Health Study over 20 years. After adjusting for age, the researchers found an association between the number of pregnancies a woman had and an increased risk of A-fib (P = 0.004 for trend). This relationship was strengthened after further adjusting for body mass index, diabetes, and other CV risk factors.

“[T]he point here is not to discourage women from having children,” Wong said in a press release. His team suspects that “repeated exposure to metabolic, physiological, and hormonal changes during pregnancy may predispose to [A-fib] in later life,” they write in the study, encouraging further research in this field. They also caution that since most participants were of European descent, the results may not be generalizable to a broader population.

In the second paper, Lauren Tanz, MSPH (Harvard T.H. Chan School of Public Health, Boston, MA), and colleagues analyzed data from more than 70,000 women enrolled in the longitudinal Nurses’ Health Study II to investigate the relationship of preterm delivery (< 37 weeks) with eventual cardiovascular disease. After adjustment for several demographic and lifestyle factors, women who delivered preterm in their first pregnancy had a 42% higher risk of CV disease compared with those who delivered after 37 weeks (HR 1.42; 95% CI 1.16-1.72). Moreover, those who delivered at 32 weeks or earlier were at twice the risk (HR 2.01; 95% CI 1.47-2.75), even only among women whose first pregnancy was not complicated by hypertensive disorders.

This knowledge should give clinicians something else to help risk stratify their patients, Tanz and colleagues write. “Ultimately, preterm delivery may be a useful prognostic tool to identify high-risk women early in life who would benefit from early screening, prevention, and treatment,” they conclude.

“Women and men share common features in the manifestations and pathophysiology of heart and vascular disease, and understanding of those pathophysiological mechanisms is incomplete. At the same time, significant differences exist that have largely been neglected by regulatory, industrial, funding, and research policies,” the editorialists note. They pledge that future issues similar to this special edition will lead “the way to a future free of these scourges.”

  • Wong JA, Rexrode KM, Sandhu RK, et al. Number of pregnancies and atrial fibrillation risk: the women’s health study. Circulation. 2017;135:622-624.

  • Tanz LJ, Stuart JJ, Williams PL, et al. Preterm delivery and maternal cardiovascular disease in young and middle-aged adult women. Circulation. 2017;135:578-589.

  • Reimold SC, Hill JA. Inaugural Go Red for Women Issue. Circulation. 2017;135:493–494.

  • This study by Wong et al. was supported by grants from the National Heart, Lung, and Blood Institute (NHLBI) and the Women’s Health Study was supported by grants from the NHLBI and National Cancer Institute.
  • The study by Tanz et al. was funded by grants from the NHLBI and supported by awards from the American Heart Association.
  • Wong reports receiving support from the Canadian Institutes of Health Research Fellowship award and the Arthur J.E. Child Cardiology Fellowship.
  • Tanz reports no relevant conflicts of interest.