Define menarche and menopause

Menarche is the first menstrual cycle, or first menstrual bleeding, in female humans. From both social and medical perspectives, it is often considered the central event of female puberty, as it signals the possibility of fertility.

Girls experience menarche at different ages. Having menarche occur between the ages of 9–16 is considered normal. The timing of menarche is influenced by female biology, as well as genetic and environmental factors, especially nutritional factors.

Menopause, also known as the climacteric, is the time in women's lives when menstrual periods stop permanently, and they are no longer able to bear children.

Menopause usually occurs between the age of 48 and 52. Medical professionals often define menopause as having occurred when a woman has not had any menstrual bleeding for a year. It may also be defined by a decrease in hormone production by the ovaries.