Women who have long and irregular periods may have an increased risk of dying early, finds study
Women who experience irregular or long periods in adolescence and throughout adulthood are more likely to die early, before the age of 70, than women reporting regular or short cycles, according to a new study. Researchers found that women who reported that their usual cycle length was 40 days or more at ages 18-22 years and 29-46 years were more likely to die prematurely than women who reported a usual cycle length of 26-31 days in the same age ranges. Death rates per 1,000 person-years for women reporting very regular cycles and women reporting always irregular cycles were 1.05 and 1.23 at ages 14-17 years, 1.00 and 1.37 at ages 18-22 years, and 1.00 and 1.68 at ages 29-46 years.
The findings highlight the need to consider the menstrual cycle as a critical sign of general health in women throughout their reproductive lifespan, suggests the research team. “Our results emphasize the need for primary care providers to include menstrual cycle characteristics throughout the reproductive years as additional vital signs in assessing women’s general health status and point to potential lifestyle interventions to manage risk among women with menstrual cycle disorders that might have long-term adverse health consequences,” write authors in the study published in BMJ. The team includes experts from Harvard TH Chan School of Public Health, Harvard Medical School, and Michigan State University, among others.
Irregular and long menstrual cycles have been associated with a greater risk of coronary heart disease, cancer, mental health problems, and multiple other common chronic conditions. However, evidence linking irregular or long periods with death is scant. Accordingly, the authors decided to investigate whether irregular or long menstrual cycles throughout the life course are associated with premature death, which is before 70. The analysis is based on data from 79,505 premenopausal women (average age 38 years) with no history of cardiovascular disease, cancer, or diabetes who were taking part in the Nurses’ Health Study II. Women reported the usual length and regularity of their menstrual cycles at ages 14-17 years, 18-22 years and 29-46 years.
During 24 years of follow-up, 1,975 premature deaths were documented, including 894 from cancer and 172 from cardiovascular disease. After taking account of other potentially influential factors, such as age, weight, lifestyle, and family medical history, the authors found that irregular and long periods in adolescence and adulthood are associated with a greater risk of early death, before the age of 70. “Women who reported always having irregular menstrual cycles experienced higher mortality rates than women who reported very regular cycles in the same age ranges. The mechanisms underlying these associations are likely related to the disrupted hormonal environment,” the findings state. The associations were strongest for deaths related to cardiovascular disease than for cancer or death from other causes. They were also slightly stronger among women who smoked.
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Since this is an observational study, it cannot establish cause, and the researchers point to some limitations, such as relying on recall of menstrual cycle characteristics, which may not have been completely accurate. However, strengths included a large number of participants with a high follow-up rate over many years, and the availability of menstrual cycle data at three different points across the reproductive lifespan, they explain.
What are other experts saying?
Several experts, who were not part of the study, have said that while the current analysis makes some important points, one should not be alarmed by the findings. “This study should not be a cause of concern for all young women with irregular and/or long menstrual cycles as there are many other factors involved, but I would hope that the information would raise awareness and encourage healthcare providers (as well as women) to investigate irregular menstrual cycles; an approach that has potential to improve reproductive health and subsequent longer-term outcomes,” explains Rachel Tribe, professor of maternal and perinatal sciences, Kings College London.
Dr Abigail Fraser, a reader in epidemiology, University of Bristol, says that while the authors have accounted for multiple potential confounders and have been very measured in their interpretation, they do not adjust for a socio-economic position (in childhood or adulthood), which could be confounder and this is a limitation.
According to Dr Jacqueline Maybin, senior research fellow and consultant gynecologist at the MRC Centre for Reproductive Health, University of Edinburgh, the analysis is a “real step forward” in closing the data gap that exists in women’s health. These data will encourage future interrogation of menstrual symptoms and pathologies as an indicator of long-term health outcomes and may provide an early opportunity to implement preventative strategies to improve women’s health across the lifespan, she suggests.
Maybin emphasized that it is also important to remember that irregular menstruation is a symptom and not a diagnosis. “Therefore, a specific underlying cause of irregular menstruation may increase the risk of premature death, rather than the irregular bleeding, per se. We already know that women with polycystic ovarian syndrome (PCOS), a leading cause of irregular periods, have an increased risk of diabetes, high blood pressure, and cancer of the womb. It is important that women with PCOS speak to their doctor to reduce these risks,” writes the expert. She adds, “The findings reported are interesting but it should be stressed that this is an association between irregular menstrual cycles and early death. This means that there is no current evidence that having irregular cycles causes early death and the association may be due to chance.”
Maybin also argues that all study participants were nurses, some of whom will have worked very irregular hours. “Shift work, particularly night shifts, has been shown to have a significant impact on long-term health. Disruption of the circadian rhythm has also been shown to affect menstrual regularity, with shift-workers more likely to have irregular and long menstrual cycles. This was not accounted for in the analysis and may limit the application of these findings to the general population,” she explains.