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 cup have a great impact on the environment. Most of the pads and tampons are made of cotton and plastic. Plastic takes about 50 or more years and cotton starts degrading after 90 days if it's composted. Given that the menstrual cup is reusable, its use greatly decreases the amount of waste generated from menstrual cycles, as there is no daily waste and the amount of discarded packaging decreases as well. After their life span is over, the silicone cups are put in landfills or incinerated. Menstrual cups may be emptied into a small hole in the soil or in compost