What is puberty?
Puberty is the period of growth and development in which children and adolescents develop adult physical features, such as breasts or pubic hair, and become able to reproduce (have and create babies). For girls, puberty usually begins at age 8½ to 10 years and lasts about 4 years.
When puberty starts in a girl depends on the following:
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Weight: Overweight girls usually start puberty earlier
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Nutrition: Girls who don't have access to or can't absorb proper nutrition start puberty later
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Race: Puberty usually starts earlier in black and Hispanic girls and later in white girls
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Genetics: Daughters of mothers who started puberty early are likely to also start early
What causes puberty?
The entire reproductive system, including puberty, is controlled by hormones. Hormones are chemical messengers made in certain parts of your body that travel through the blood to signal other parts of the body what to do.
Puberty in girls starts when hormones released by the brain cause the ovaries to develop. The ovaries then release the hormone estrogen. Estrogen causes development of the girl's reproductive system, including her:
Menstrual periods usually begin a few years after puberty starts.
What changes happen in puberty?
The following physical changes take place, usually in this order:
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First, breast growth—this usually happens between ages 8 and 13
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Shortly after, hair starts to grow in the armpits and genital area
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A growth spurt in height happens—growth usually slows down when periods start
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Periods (menstruation) start about 2 to 3 years after the start of breast growth
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Girls usually stop growing in height between ages 14 and 16
The first period usually happens about age 13 though it can be anytime between ages 10 and 16. Periods may not come regularly at first. It can take up to 5 years for the menstrual cycle to become regular. As girls grow, their body shape will change. Their hips and thighs get bigger, and they get more body fat. This is a normal part of puberty in girls.
Milestones in Sexual Development
What can go wrong with puberty?
Problems with puberty usually involve hormones. There are many different hormone problems that result in too few hormones so that:
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Puberty is delayed or doesn't start at all
Less often, there are too many hormones and the girl has:
