PUBERTY

DEFINITION
Puberty is the sequence of events in which physical changesoccur, resulting in physical properties of the adults and the abilityto reproduce. Physical changes are regulated by changinghormone levels that result in the pituitary gland, luteinizinghormone and follicle-stimulating hormone.

At birth, levels of these hormones are high, but decreased in recent months and remained low until puberty. At the beginning ofpuberty, levels of luteinizing hormone and follicle-stimulating hormone increases, stimulating the production of sex hormones.

Increased levels of sex hormones (especially estrogen) causedphysical changes, including the maturation of the breast, ovary,uterus and vagina. Normally, these changes occur sequentiallyduring puberty, resulting in sexual maturity.

The first change of puberty usually starts on the growth of breast(enlarged breasts). In young women living in the United States, this change usually occurs around age 8 to 13 years. Soon after, the pubis, and underarm hair starts to grow. The distancebetween the breasts enlarged to a menstrual period is usuallyabout 2 ½ years. In the United States, girls, on average, have afirst period when they were nearly 13 years. The body shapes of women change, and percentage of body fat increases.

Encouragement of growth accompanying puberty begins roughlywhen the pubic and underarm hair starts to grow. Relatively rapidgrowth in early puberty (before the menstrual period begins) andpeak around the age of 12 years. Then progress is very slow,usually stops between the ages of 14 and 16 years.