Girls go through a process called puberty, during which their body experiences many changes in order to allow it to physically reproduce and become an adult.

One change is that girls begin to get their menstrual periods. Menstrual periods occur once a month and can last from a few days to a week. Some girls have cramps during their periods while others do not. It’s important for girls to understand that their first period signals the beginning of ovulation and their body’s ability to get pregnant if they were to have unprotected sex. Once a month, a hormone in the girl’s brain signals her ovaries to release an egg or ovum (a process called ovulation). The hormone estrogen is also released to signal the girl’s uterus to build up its lining. If an egg is not fertilized within 12 to 24 hours after ovulation, the egg dies and disintegrates while still in the uterine tube. Two weeks later, when the uterus realizes there is no fertilized egg, the built-up lining of the uterus is released or shed during a girl’s menstrual period.

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There are many other physical, emotional and social changes of puberty as well, and it generally takes five to seven years for all of the changes to be complete. Additional physical changes of puberty include a growth spurt during which girls become taller as well as hair growth under their arms, on their legs and around their genitals. Their genitals will grow in size as their whole body grows larger. They may also experience acne, and their sweat may now have a strong odor.

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There are also emotional changes during puberty, including mood swings, experiencing sexual feelings, being interested in other people in a new romantic and/or sexual way and often feeling a need for more privacy from parents and/or siblings.

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