What are the stages of puberty in girls?

In the first stage of puberty (which generally takes place between the ages of 8 and 11), the silent indicators of puberty are surging inside the body, as ovaries respond to hormones such as LH and FSH and begin cultivating estrogen-producing abilities.

The second stage of puberty generally occurs when a girl is 11 or 12 years old. Breasts begin to enlarge, or "bud." As the areola darkens and rises and some transitional breast tissue forms, buds develop. This generally precedes all other visible signs of adolescence, although it is not unusual for pubic hair to sprout before the breasts show signs of maturing. A growth spurt will occur.

During the third stage of development, growth of the breasts and pubic hair persists. Hair may be visible in armpits and the vagina grows in size. This stage typically includes girls ages 12 and 13 (although any girl aged 9 to 15 may go through this stage). By this stage in development, seven out of every 10 girls will have begun her menstrual period. Once the body accepts its signal from the brain to kick off puberty, menstruation typically begins in less than three years.

In the fourth stage of puberty for females (usually around ages 13 and 14), the accelerated growth of height will usually subside. The adolescent girl's level of body fat will climb to higher adult levels, abating at about 26 percent body fat. Growth of pubic and underarm hair will carry on and become fuller and coarse. If the menstrual cycle has started, ovulation may initially be irregular as it establishes its rhythm. While it is now common for girls at 12 or 13 years of age to be menstruating, this was not the case more than 100 years ago. Back then, most girls were 15 when they experienced their first periods (shifts in nutrition, health and the environment are believed responsible).

Stage five represents the fully matured young woman (usually around ages 14 to 17, though it is not atypical for a girl to be as old as age 19) who has progressed through all preceding stages of puberty. The young woman has likely reached her maximum adult height by this time. Her breasts have probably reached their full size, and her pubic hair is fully matured. The young woman's periods and ovulation occur predicatably. Her cardiovascular, skeletal and muscle systems are all now completely formed.

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