Some more menstrual facts on #MenstrualHygieneDay:
A third of women, once a year have a period two weeks early or late.
Artificial lights may shorten and regulate menstrual cycle.
The average woman in an industrialized society menstruates 450 times in her life. Women in agrarian regions menstruate about 150 cycles in a lifetime. Prehistoric women menstruated only about 50 times.
Each menstrual cycle is created by a unique eff and its surrounding cells, the cells produce hormones controlled by feedback from the brain and pituitary hormones.