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
Menstrual psychosis Menstrual psychosis Menstrual psychosis is a debated form of psychosis with a brief, sudden onset related to the menstrual cycle. The symptoms associated to it are dramatic and may include delirium, mania or mutism. Most psychiatrists do not recognise the condition. Only 80 established cases are reported in medical literature and most of them were described by 19th century physicians. There is evidence to suggest that it may be linked to postpartum psychosis. Menstrual psychosis is a rare form of severe mental illness, with the following characteristics: It shares clinical features with, and presents similarly to, postpartum psychosis. Researchers Deuchar