The menstrual cycle refers to the cycle of changes a woman’s reproductive tract goes through every month. This involves ovulation (release of the female’s egg from the ovary allowing it to be fertilised) and menstruation (monthly flow of blood due to shedding of the uterus lining when the egg is not fertilised. The average duration of this cycle is approximately 28 days.
More on female reproductive system.
More on the menstrual cycle.