Published on May 24 in the Journal of the American Heart Association, a recent study reveals a significant association between the length of a woman’s menstrual cycle and her risk of cardiovascular disease events. This includes heart attacks and atrial fibrillation (Afib).
The findings underscore the menstrual cycle’s importance as a health indicator, particularly for heart health, according to Stephanie Faubion, MD, the director of the Center for Women’s Health at Mayo Clinic in Jacksonville, Florida.
Irregular Period Cycles Aren’t ‘Necessarily Benign’
According to Dr. Faubion, “This study adds to the accumulating literature that irregular menstrual cycles are not necessarily benign. Previous studies have linked irregular menses with multiple cardiovascular disease risk factors, including insulin resistance, high cholesterol, high blood pressure, and chronic inflammation.”
Dr. Faubion also serves as the medical director for the North American Menopause Society and was not involved in the study.
What’s the Length of a ‘Regular’ Menstrual Cycle?
The regularity of a menstrual cycle is typically defined as the time elapsed from the first day of one period to the first day of the next. The average menstrual cycle spans 28 days, with anything between 21 and 35 days considered regular. Deviations from this range are deemed regular, a condition affecting approximately one in five women, as per the Merck Manual.
A regular menstrual cycle length reflects the healthy functioning of interconnected hormone systems involving the hypothalamus, pituitary gland, and ovaries, serving as a crucial indicator of overall health, as explained by the study’s authors.
40 Percent Higher Risk of Afib Associated with Irregular Cycle Length
To investigate the link between menstrual cycle length, heart disease, and specific cardiovascular events in women, researchers analyzed data from nearly 60,000 women enrolled in the UK Biobank. A regular cycle was defined as lasting between 22 and 34 days.
At the beginning of the study, participants had an average age of 46, were 92 percent white, were free of heart disease, and had not yet experienced menopause. Health data was collected through four follow-up visits conducted from 2006 to 2010, 2012 to 2013, and in 2014 and 2019.
Over a median follow-up period of 12 years, 1,623 cardiovascular events occurred, including heart disease, heart attacks, atrial fibrillation, stroke and heart failure.
According to the researchers, these were the key findings of the study:
A menstrual cycle shorter than 21 days or longer than 35 days was associated with a 19 percent higher risk of heart disease and a 40 percent higher risk of atrial fibrillation than a regular menstrual cycle length.
- Shorter menstrual cycles were associated with a 29 percent higher risk of CVD events, including coronary heart disease, heart attack, atrial fibrillation, stroke, and heart failure. Longer menstrual cycles were associated with an 11 percent higher risk of those CVD events, compared with regular-length menstrual cycles.
- Shorter menstrual cycles were associated with a 38 percent higher risk of atrial fibrillation, and longer menstrual cycles were associated with a 30 percent higher risk of atrial fibrillation, compared with regular-length menstrual cycles.
- Researchers found no connection between menstrual cycle length and an increased risk of stroke or heart failure.
Notably, these elevated risks of cardiovascular disease persisted even after adjusting for various potential influencing factors, such as age, ethnicity, body mass index, smoking and drinking habits, physical activity, baseline cholesterol levels, history of high blood pressure or type 2 diabetes, oral contraceptive use or hormone replacement therapy history, and family history of heart disease or stroke.
Findings Highlight the Importance of Monitoring Menstrual Cycles
Given these findings, the study’s senior author, chief physician and professor at Nanfang Hospital of Southern Medical University in China, Huijie Zhang, MD, PhD, emphasized the importance of informing women with irregular menstrual cycles about their heightened risk of heart disease.
She explained in a press release that this is especially significant considering the prevalence of heart disease in Western countries, where it ranks as the leading cause of death in women, accounting for approximately one in every five female deaths.
“These findings have important public health implications for the prevention of atrial fibrillation and heart attack among women and highlight the importance of monitoring menstrual cycle characteristics throughout a woman’s reproductive life,” said Dr. Zhang.
Nevertheless, the study has certain limitations, such as self-reported menstrual data from participants and the potential influence of menopausal transitions on menstrual cycles, Additionally, the study’s predominantly white participants may limit its generalizability to women from diverse racial or ethnic backgrounds or younger women.
Irregular Periods Can Be Caused by Stressing the Body
According to Dr. Faubion, these findings make sense and support the fact that irregular menses are an indicator for poorer cardiovascular health. She says, “Women may have irregular menses for a number of reasons, but among them are overexercising, restrictive eating patterns, and high levels of stress,” she says.
Moreover, the director of Women’s Cardiovascular Health at Penn Medicine in Philadelphia, Monika Sanghavi, MD, said that although the association found in the study makes sense, the menstrual cycle length itself is likely not the cause of the increased risk. “Rather, it’s likely the underlying cardiometabolic health problems causing the abnormal menstrual cycle length that are to blame. However, either way, we can use this information to target lifestyle interventions in this population,” explains Dr. Sanghavi.
Notably, Dr. Sanghavi was not involved in the research.
Reproductive Health History Considered Important Part of Heart Risk Assessment
Dr. Sanghavi adds that the study adds to the growing body of evidence that reproductive health history is an important part of a woman’s cardiovascular health assessment.
“For a long time, women’s reproductive health has lived on an island of its own that only ob-gyns and some primary care physicians addressed. However, as a cardiologist, I believe we must begin to build bridges to the island and incorporate reproductive health assessment, including menstrual cycle history, pregnancy history, and menopause, as part of a comprehensive assessment for women — or else we are truly not caring for the whole patient,” she says.
However, while more research is still needed, Nieca Goldberg, MD, the medical director of Atria New York Cityand a clinical associate professor of medicine at the NYU Grossman School of Medicine explains that these findings can also be used to begin a conversation with women on heart disease prevention, which in turn will help them identify risk factors that can be treated or modified.
Dr. Goldberg adds that knowing your numbers and following lifestyle programs that are designed to improve eating patterns, reduce stress, promote regular exercise, improve sleep, and stop smoking are all important strategies to help prevent heart disease.
Use an App to Help Tell If Your Cycle Is Regular
Not everyone knows whether they have a regular cycle or not. Thankfully, there are a number of apps that can be downloaded online that can help you keep track of your data. However, some experts worry about the lax privacy practices of some companies.
Consumer Reports recommends three different period tracking apps, namely Drip, Euki and Periodical for their strong privacy practices.
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