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 leave a campaign for menstrual leave for female employees at Toyota. The union asked for 12 paid days of menstrual leave for a woman per year. Menstrual leave policies exist in some Asian countries, although individual companies in countries that do not have national laws may choose to implement such policies. In Indonesia, under the Labor Act of 1948, women have a right to two days of menstrual leave per month. In Japan, Article 68 of the Labour Standards Law states "When a woman for whom work during menstrual periods would be specially difficult has requested leave, the employer shall not