Puberty: Normal Growth and Development in Girls

How long does puberty last?

In girls, puberty usually starts between ages 9 and 14. Once it begins, it lasts about 2 to 5 years. But every child is different. And there's a wide range of what's normal. Your child may begin puberty a little earlier or later and finish sooner or later than their friends. If you have questions or concerns about your child’s development, talk to their healthcare provider.

Physical changes during puberty

• Height and weight:

  • About 20% of adult height is gained during puberty. Girls begin to grow taller fairly early in puberty.

  • About 50% of normal adult weight is gained during puberty. The hips, thighs, breasts, and stomach often gain more weight than other areas. Also, a girl’s body fat percentage often doubles by the end of puberty.

• Sexual development and hair growth:

  • At the start of puberty, breasts start to develop. Usually this begins around age 9 or 10. But it can happen earlier or later. This is called breast budding. At this time, a hardening can be felt under the nipple. One breast often starts to grow before the other. Breast budding can cause the breasts to be sore or even painful. This is normal and not a sign of a problem.

  • Pubic hair begins to grow next. (In about 10% of girls, this happens before breast bud development). The hair comes in thinly at first. But over time, it grows darker and coarser. Leg and underarm hair also begins to grow 1 to 2 years after pubic hair starts growing. 

  • Girls usually begin having periods (menstruating) between ages 9 and 16. The average age is 12, but starting periods earlier or later is normal. Before actual periods begin, girls may have several months of clear or whitish discharge. This is normal. It's also normal for periods to be irregular during the teen years. But a girl can still get pregnant even if her periods aren't regular.

• Acne and body odor:

  • Hormones that increase during puberty can cause acne on the face and body.

  • Hormones also increase sweating and cause a stronger body odor.

Reassuring your child

• Your child may be concerned that their peers are more or less developed than they are. Explain to your child that kids of the same age may be at different stages of puberty. Your child’s growth, whether slow or fast, is happening at the right rate for them.

• Help your child adjust to their changing body. Offer solutions for body odor and acne (such as bathing more often, using deodorant, and using acne products).

• Your child will likely feel uncomfortable talking about sexual changes with you. Let them know you're there to talk to. You may also think about giving your child a book with information about puberty that they can read on their own.

Exams during puberty

As puberty begins, it’s important for your child to see their healthcare provider once a year. Keep bringing her in for regular health screenings, at least once a year. Know that, during puberty, health screenings will include an exam of your child without clothes. This lets the healthcare provider see how your child is progressing physically through puberty. Reassure your child that this exam is normal and expected. Also, parents may be asked to leave the room for part of the exam. This is so the child and the healthcare provider can have an honest and open discussion. If you have any questions or concerns, talk to your child’s healthcare provider.