Women’s heart health is among the most understated puzzles in scientific research. Akin to a Rubik’s cube, the challenge is one of moving the pieces enough to address gender barriers like delayed diagnosis and lack of research around gender-specific stressors. Then, a worthy addition in this pursuit is new research that looks into how a woman’s reproductive history can help predict their future risk of heart failure.

Published in the Journal of the American College of Cardiology this month, the study explores histories of infertility among 38,528 postmenopausal women over a period of 15 years. The researchers tapped into the database of the Women’s Health Initiative (WHI), which has been collating details of woman’s reproductive history since the 1990s. On following up with the participants post the 15-year mark, the researchers found women who experienced infertility had a 16% higher risk of heart failure, as compared to women who did not share a similar reproductive history.

“We are beginning to recognize that a woman’s reproductive history tells a lot about her future risk of heart disease,” said first author Emily Lau, a cardiologist, and director of the Menopause, Hormones and Cardiovascular Clinic at Massachusetts General Hospital. “Whether a woman has difficulty becoming pregnant, what happens during her pregnancies, when she transitions through menopause all influence her risk of heart disease later in life.”

Cardiovascular care is plagued by a pressing gender problem; researchers have only begun to uncover the biological, medical, and social bases of differences that prevail. “Cardiovascular disease in women remains understudied, under-recognized, underdiagnosed, and undertreated,” a recent report by the Lancet stated. With cardiovascular disease being the “leading cause of death in women globally,” delayed diagnoses can turn fatal.

The troubles that women experience to get a diagnosis are cut out by entrenched gender biases. Women are more likely to be misdiagnosed due to a low index of suspicion; complaints of chest pain are very often underestimated and dismissed. The reason for the discrepancy in gender-based data is simply gendered bias — “heart attack has traditionally been considered a male disease,” said Dr. Martinez-Nadal, one of the researchers of the Lancet study. This explains why physicians may attribute symptoms of cardiovascular disease in women to stress or anxiety — “probably fuelled further by the stereotype that women are more emotional,” as The Swaddle had noted before.

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Then, research that uses one’s reproductive history as a predictor of cardiovascular health has much to offer. “Infertility is one of many cardiovascular risk factors, such as hypertension and high blood pressure, but reproductive history is not routinely considered as part of the cardiovascular risk assessment,” explained Lau.

The present study looked at two types of heart failure: heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). The former, HFpEF, is far more common in women; but it’s a “challenging condition” owing to a lack of understanding around what causes this variation of heart failure — subsequently limiting treatment opportunities.

The findings then become important “because heart failure with preserved ejection fraction is more prevalent in women. We don’t understand why we see HFpEF more in women. Looking back in a woman’s early reproductive life may give us some clues as to why,” the researchers noted.

What links infertility and heart failure in women? While there is some research in the past to link women’s infertility with a higher occurrence of cardiometabolic (a spectrum of conditions that include diabetes, cardiovascular disease, etc.) risk factors. Yet, the exact underpinnings of what makes infertility a variant in determining heart health will be the next steps of the research.

For now, using one’s reproductive history can act as a litmus test to navigate another critical health concern. “We cannot change a woman’s history of infertility,” Lau concedes. “But if we know a woman has had a history of infertility, we can be more aggressive about counseling her about other modifiable risk factors including high blood pressure, high cholesterol, smoking, and beyond.”