Breasts usually began to develop about one year before the onset of menstruation. It is one of the main evidence of puberty in young girls.

Menstrual cycle is the term applied to the recurrent series of changes in a woman’s reproductive system of which menstruation is the outward manifestation. Girls tend to mature one or two years earlier than boys.

The teenage period between the ages of 12 and 25 is considered the adolescent period. It is the time when there is the most rapid growth and the most sudden changes in physical, psychological and physiological development.