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Puberty in Girls


The Manual's Editorial Staff

Last full review/revision May 2020
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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:

  • Weight: Overweight girls usually start puberty earlier

  • Nutrition: Girls who don't have access to or can't absorb proper nutrition start puberty later

  • Race: Puberty usually starts earlier in black and Hispanic girls and later in white girls

  • Genetics: Daughters of mothers who started puberty early are likely to also start early

What causes puberty?

The entire reproductive system Overview of the Female Reproductive System The female reproductive system is the system in a woman's body with the purpose of making babies. The female reproductive system includes both external genital organs (outside the body) and... read more , 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:

  • Breasts

  • Vagina

  • Ovaries (the pair of organs where eggs are made and stored)

  • Uterus (the organ where a fetus grows before being born)

What changes happen in puberty?

The following physical changes take place, usually in this order:

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 Menstrual Cycle A menstrual cycle is the process a woman's reproductive system goes through each month to release an egg from the ovaries and make a pregnancy possible. A menstrual period (menstruation) is... read more 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

During puberty, sexual development occurs in a set sequence. However, when the changes begin and how quickly they occur vary from person to person. For girls, puberty begins at age 8 1/2 to 10 years and lasts about 4 years. The chart shows a typical sequence and normal range of development for the milestones of sexual development.

Milestones in Sexual Development

What can go wrong with puberty?

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