Menstruation, in some cultures, has been considered mystical, while in others, menstruating or postmenstrual women have been seen as "impure". This perception varies widely across cultures. For example, Chinese sages regarded menstrual blood as the essence of the earth. At the other extreme, between the 8th and 11th centuries, the Christian Church denied menstruating women the right to life. It is believed that the concept of the calendar evolved first in women, as they followed the rhythms of their bodies in relation to their observations of the moon. Some refer to Chinese women's establishment of the lunar calendar as early as 3000 years ago. It has even been claimed that the origins of mathematics may derive from the concept of counting that is so deeply embedded in the menstrual cycle. It is worth paying attention to the quality of life issues that are associated with menstruation. From sponges, to menstrual cups, which were meant to be inserted into the vagina to collect blood, to reusable pads, women have had to use a wide array of menstrual products. According to a DHHS type document (2002), disposable pads were developed after World War I and marketed in the 1920s; they were manufactured using materials and techniques similar to those used in combat bandages. This type of technology was later used to develop things such as adult diapers and special pads for adults with urinary incontinence. Tampons were developed during the same time period, and were widely used in the 1940s. However, there were several concerns with the use of tampons. One concern was that tampons would compromise a girl's virginity. Fears about their safety intensified in 1980, when toxic shock syndrome in young women (813 cases and 38 deaths) was linked to a type of superabsorbent tampon. More recently, false rumors spread via the Internet also raised concerns that tampons may contain asbestos and dioxin.
