Menstrual cycle characteristics a marker of general health

By Nicole MacKee
Menstrual cycle characteristics should be considered ‘vital signs’ in assessing the general health of women of reproductive age, say researchers who have found a link between irregular and long cycles and premature mortality.

An evaluation of almost 80,000 participants in the Nurses’ Health Study II, published in The BMJ, found that women who reported irregular or long menstrual cycles in adolescence or throughout adulthood had a higher risk of death before the age of 70 years.

During 24 years of follow up, 1975 premature deaths – including 894 from cancer and 172 from cardiovascular disease – were reported.

Participants (then aged 29 to 46 years) were asked to recall the usual length and regularity of their menstrual cycles when in adolescence (aged 14 to 17 years), young adulthood (aged 18 to 22 years) and adulthood (aged 29 to 46 years).

After adjusting for confounders such as age, weight and family history of myocardial infarction, stroke or diabetes, the researchers found that women who reported always having irregular menstrual cycles or no periods in adolescence, young adulthood and adulthood had an increased risk of premature death during follow up (hazard ratios of 1.18, 1.37 and 1.39, respectively) compared with women with regular cycles.

Also, the researchers reported, women who reported a usual menstrual cycle length of 40 days or longer were more likely to die earlier than women with a usual cycle length of 26 to 31 days.

Professor Gita Mishra, Professor of Life Course Epidemiology at the School of Public Health, University of Queensland, said these findings were ‘interesting’, although the increases in risk were modest.

Professor Mishra noted that the study participants were nurses, which may affect the generalisability of the findings.

‘In addition, the information on menstrual cycles was asked only once in midlife – between ages 29 and 46 years – so it is not a very precise measure. That said, the findings are not surprising as they fit into a pattern of evidence where previous studies have found some reproductive characteristics linked with adverse outcomes, such as early menopause (less than age 45 years) also being associated with premature mortality.’

Professor Mishra agreed with the researchers’ conclusion that menstrual cycles should be considered vital signs in primary care consultations for women.

‘Findings from this study do add to the evidence that women’s reproductive characteristics, such as their menstrual patterns, represent markers for their general health and so these should be included in medical assessments,’ she said. ‘Further research is still needed to enable health professionals to understand the full implications of this information and act accordingly.’
BMJ 2020; 371: m3464;