Culture and menstruation the ideal of synchronised tidal, lunar, menstrual and seasonal periodicities whose overall harmony (it is believed) confers spiritual power and fertility. To many, such cultural associations appear persuasive in view of the fact that in humans, the menstrual cycle quite closely approximates the moon's 29.5-day synodic cycle, unlike in chimpanzees (~36 days) or bonobos (~40 days). Statistical information from hunter gatherers is lacking, but where large-scale western studies focus on women's peak reproductive years—removing outlier values—the cycle length gravitates around 29.1–29.5 days, while the figure for women in their thirties shortens toward 28 days. In no extant human population has
Centre for Menstrual Cycle and Ovulation Research stated vision was to 'reframe scientific knowledge of the menstrual cycle and ovulation in a woman-centered context.' CeMCOR is now located at Vancouver General Hospital in the Gordon and Leslie Diamond Health Care Centre. Staff includes 15 clinicians and 9 trainees. It is guided by both a Community Advisory Council and a Scientific Advisory Council composed of endocrinologists, epidemiologists, gynecologists, nutritionists, psychologists, and sociologists. CeMCOR published over 50 scientific papers in its first 10 years, as well as 4 books. Areas of research include menstruation and ovulation, bone health, premenopausal breast cancer, polycystic ovary syndrome (PCOS), and perimenopause. CeMCOR has