A study published in JAMA Network Open found that irregular and long menstrual cycles are associated with an increased risk of cardiovascular disease (CVD), particularly coronary heart disease (CHD). The researchers noted that the risk of CVD increased as women with irregular and long cycles aged and suggested that polycystic ovary syndrome (PCOS) may contribute to many of these cases.
Based on data from the Nurses’ Health Study II, the study analyzed menstrual cycle regularity and length reported by 80,630 participants. Over a follow-up period of 24 years, 2.3% of the cohort experienced a CVD event, with 1.5% being CHD and 0.8% stroke cases. Women who reported irregular cycles or no periods during adolescence and early adulthood, as well as during their 30s and 40s, had a higher risk of developing CVD than those with regular cycles at the same ages. Similarly, women with longer or highly irregular cycle lengths experienced a greater CVD risk than those with shorter and more regular cycles.
The researchers highlighted that while women with irregular or long cycles were more likely to have certain cardiovascular risk factors, such as hypercholesterolemia, chronic hypertension, and type 2 diabetes, these factors explained only a small portion of the associations between menstrual cycle characteristics and incident CVD. They proposed that underlying PCOS, characterized by irregular cycles and ovulatory dysfunction, could be responsible for the observed associations, as PCOS is associated with increased cardiovascular risks.
In conclusion, the study suggests that irregular and prolonged menstrual cycles may be markers for identifying women more likely to develop cardiovascular events later in life, with PCOS potentially playing a role in these associations.