Menstrual cycle shortest and longest cycle lengths is considered very irregular. The average menstrual cycle lasts 28 days. The variability of menstrual cycle lengths is highest for women under 25 years of age and is lowest, that is, most regular, for ages 25 to 39. Subsequently, the variability increases slightly for women aged 40 to 44. The luteal phase of the menstrual cycle is about the same length in most individuals (mean 14.13 days, standard deviation 1.41 days) whereas the follicular phase tends to show much more variability (log-normally distributed with 95% of individuals having follicular phases between 10.3 and 16.3 days).
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