Women with irregular periods appear to face a significantly higher risk of heart disease, a study has found.
Up to one-fifth of American women of childbearing age – about 12 million of them – experience an abnormal period, which occurs when the length of their menstrual cycle unexpectedly falls outside the regular range, usually less 21 days or more than 35 days.
According to a team of researchers in China, irregular periods can be an inconvenience at best for millions of women, but at worst it increases women’s risk of heart disease by 19% and irregular heartbeat by 40%.
The study followed more than 58,000 women for 12 years, after which researchers found that 3.4% of women with irregular cycles developed heart disease, compared to around 2.5% of those with normal periods. .
Dr Huijie Zhang, a professor at Southern Medical University in China and lead author of the study, said: “These findings have important public health implications for the prevention of atrial fibrillation and heart attacks in women and emphasize the importance of monitoring the characteristics of the menstrual cycle throughout a woman’s reproductive life.
An analysis of data from over 58,000 women found that both short (less than 21 days) and long (more than 35 days) menstrual cycles were associated with a higher risk of developing heart disease, atrial fibrillation and seizures. cardiac.
The extensive study reflected health data from over 58,000 healthy women in the UK who reported their cycle length at the start of a 12-year follow-up period.
The menstrual cycle is counted from the first day of one period to the first day of the next.
The study, published in the Journal of the American Heart Association, drew on extensive health data from the UK BioBank, a large-scale population health research initiative containing in-depth genetic and health information. of half a million British participants.
The average age of the participants, none of whom had cardiovascular disease at the start of the study, was 46.
After 11 years and eight months, the researchers recorded 1,623 cardiovascular “events” among the participants, including 827 incident cases of coronary heart disease, 199 heart attacks, 271 strokes, 174 cases of heart failure and 393 cases of atrial fibrillation. or irregular heartbeat. which can lead to blood clots.
More than 1.7% of women with irregular cycles developed coronary heart disease (CHD), the result of plaque buildup on the walls of the arteries which then restricts the flow of oxygen-rich blood to the heart.
But only 1.3% of women with regular periods developed coronary heart disease.
And about 0.6% of those with regular cycles developed atrial fibrillation, compared to nearly 1% of those with irregular cycles.
The link between irregular menstrual cycles and heart disease is not completely clear, although previous research has shown that they are strongly linked to various risk factors for heart disease, including high cholesterol, high blood pressure and low blood pressure. polycystic ovary syndrome.
Hormonal fluctuations that are fundamental to the menstrual cycle also influence cardiovascular function. Estrogen, which drops after ovulation but gradually increases, has protective effects on the heart.
Estrogen helps tissues and blood vessels stay soft and flexible, contributing to healthy blood circulation, maintaining low blood pressure, raising HD (good) cholesterol, and absorbing harmful free radicals.
Although irregular cycles are common, they are not healthy and actually reflect malfunctioning of the hypothalamic-pituitary-ovarian axis, the tightly regulated network of systems that control female reproduction.
Dr Zhang said: “The association between menstrual cycle characteristics and adverse cardiovascular outcomes remains unclear.
“Given the increasing prevalence of heart disease – with 45% of women in Western countries affected – and the associated mortality, there is a need to explore these risk factors.”