Menstruation, which begins at adolescence and lasts until menopause, is the regular bleeding of the vaginal line. The body starts preparing for pregnancy at this time.
Every month, as the uterus becomes ready to receive the fertilised egg, an egg is discharged from one of the ovaries at the same time. The uterus’ inner lining thickens and receives enough blood to support the developing embryo. The egg does not become fertilised since there is no contact between the sperm and the egg. Therefore, when the egg is not fertilised, the uterine lining gradually degrades and menstruation results.