Menstrual synchrony
Strassmann argued menstrual synchrony defined as menstruation overlap should be quite common. For example, the expected difference by chance between two women with 28-day cycles—which is approximately the average length of menstrual cycles of women at the age —is 7 days. Considering that the mean duration of menses is 5 days and the range is 2 to 7 days, the probability of menstruation overlap by chance should be high.
The Story of Menstruation
The film uses animated diagrams to detail the menstrual cycle. The film's narrator, who is not identified in the credits, informs the viewer that "there is nothing strange or mysterious about menstruation", and it shows women engaged in such activities as bathing, riding a horse, and dancing during their menstrual cycles. The film's narration by actress Gloria Blondell also provides advice to avoid constipation and depression, and to always keep up a fine outward appearance.