The first menstruation (or menstrual flow) begins at puberty (when the girl or woman is around 10 to 12 years of age). The first occurrence of menstruation (or periods) at puberty is called menarche. Menarche is the beginning of the reproductive life of a girl (or woman).
In other words, menarche is the time from which a girl (or woman) becomes capable of having a baby. Menstruation stops permanently when a woman reaches the age of about 45 to 50 years. With the permanent stoppage of menstruation, a woman loses her ability to bear children. She becomes infertile.
The permanent stoppage of menstruation (or periods) in a woman is called menopause. Menopause occurs in women at the age of about 45 to 50 years. A woman stops ovulating at menopause and can no longer become pregnant. Menopause is the end of the reproductive life of a woman. We can now say that the reproductive life of a woman starts at menarche and ends at menopause.