Menstruation menarche has changed little in the United States since the 1950s. Menstruation is the most visible phase of the menstrual cycle and its beginning is used as the marker between cycles. The first day of menstrual bleeding is the date used for the last menstrual period (LMP). The typical length of time between the first day of one period and the first day of the next is 21 to 45 days in young women, and 21 to 31 days in adults (an average of 28 days). Perimenopause is when fertility in a female declines, and menstruation occurs less regularly in
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