Epidemiology of Menstruation and Its Relevance to Women's Health

Abstract

The data on the menstrual cycle as a health endpoint and as a risk factor for chronic disease are inadequate. Specifically, the data on menstrual cycle length and blood loss do not have the detail on within-woman variability needed to allow women and clinicians to anticipate certain bleeding changes that tend to develop at different life stages, to distinguish between potentially pathologic alterations from short-term aberrations, and to recognize bleeding patterns that may be risk factors for the development of chronic disease. Lack of data on bleeding changes in premenopausal and menopausal women concerns many health professionals considering the many physician visits for abnormal bleeding and the prevalence of hysterectomy among women aged more than 35. Thus, development of objective criteria on how much bleeding is too much is needed so women can determine whether their daily blood loss is or is not a concern. Women also need more information on what constitutes menstrual dysfunction. Some basic research needs include definition of population patterns of gynecologic disease, identification of potentially modifiable risk factors, the influence of recreational activity in gynecologically mature women, influence of hard physical activity in the context of women's daily work life, interaction of low weight and physical activity in developing countries, effects of work stress, effects of family interactions, effects of violence, environmental risk factors (e.g., pesticides), and physiologic variation across the menstrual cycle. Research on menstrual cycle-related risk factors for chronic disease could explain women's long term health status and identify preventive strategies for premenopausal women. Current women's health research tends to ignore hormonal influences. The limited available research on immune parameters suggests that follicular/luteal classification may not be able to detect meaningful variation. In conclusion, a comprehensive research program would fill the many gaps in scientific knowledge about the menstrual cycle.