The menstrual cycle is a natural recurring cycle of changes in the female reproductive system.
The length of the menstrual cycle is calculated from the first day of bleeding to the day before your next period.
The average length of the menstrual cycle is 28 days, but this can vary between 21 – 45 days. The length of the menstrual cycle varies between people and from one cycle to the next.
The purpose of the menstrual cycle is to prepare the body for a possible pregnancy, a mature egg is produced by the ovaries and the lining of the uterus thickens to support a possible pregnancy.