Girls who experience their growth spurt earlier or later than others may need reassurance. Body weight and percentage of body fat also undergo changes in the developing adolescent. Development of breasts . Breast development continues for several years. Pubic hair .
Pubic hair begins to grow at about the same time the growth spurt occurs.
Underarm and coarser body hair . This generally appears two years after pubic hair. The beginning of menstruation is called menarche . The first menstrual period usually occurs two years after breast development begins. LH and FSH levels, although high at birth, remain low until puberty, where they increase and stimulate the production of the female sex hormones, increased levels of which, set in motion the changes associated with this time of life.