Advancements in public and medical health have led to significant improvements in age-specific mortality in various countries. Yet, a lot of countries face a burden of premature mortality. This study aims to analyze the association between the irregular menstrual cycle and the risk of premature mortality.

This prospective cohort study included a total of 79,505 premenopausal women with no history of cardiovascular disease, diabetes, or cancer. The self-reported length and regularity of menstrual cycles at ages 14-17 years, 19-22 years, and 29-46 years were analyzed. The primary outcome of the study was the hazard ratio for all-cause and cause-specific premature mortality.

At a follow-up of 24 years, 1,975 premature deaths for reported, 894 of which were from cancer, and 172 from cardiovascular disease. The findings further suggested that women who had irregular menstrual periods were at a higher risk of mortality compared to women who had regular cycles. The crude mortality rate per 1,000 person-years of follow-up was 1.05 for women who reported regular cycles and 1.23 for those who reported irregular cycles.

The research concluded that women with irregular and long menstrual cycles were at a higher risk of all-cause and cause-specific mortality compared to women with regular cycles.