The Menstrual Cycle can last between 25 to 36 days. It relies on the female hormones working in sequence to prepare an egg ready for a potential pregnancy.
Menstruation starts during the puberty years of a girls life and will cease during her menopause.
There are three phases to the menstrual cycle:
Each phase can vary in length from woman to woman, and can also change over time.
For a normal 28 day cycle the phases normally start on the following days: