Topic summary
Menstrual bleeding
Extracted from the Wikipedia article Menstrual cycle.
Menstruation
Menstruation (also called menstrual bleeding, menses or a period) is the first and most evident phase of the uterine cycle and first occurs at puberty. Called menarche, the first period occurs at the age of around twelve or thirteen years. The average age is generally later in the developing world and earlier in the developed world. In precocious puberty, it can occur as early as age eight years, and this can still be normal.