Menstrual synchrony by chance when there is menstrual cycle variability. Yang and Schank argued that when there is cycle variability (i.e., either women have irregular cycles, have cycles of different frequencies, or both), most women will have the opportunity to experience synchrony even though it is a result of cycle variability and not a result of a mechanism such as the exchange of pheromones. For example, consider two women A and B. Suppose A has menstrual cycles that are 28 days long and B has cycles that are 30 days long. Suppose further that when A and B become close friends, B
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