What is puberty?

Puberty is the time of life when a child develops, among other things, physical changes as they transition into adulthood. Physical changes usually begin as early as 8 years and as late as age 13 in girls, and between ages 9 and 14 for boys. Hormones that increase during puberty can cause acne on the face and body, and increase sweating.

At this time, a girl’s ovaries and a boy’s testes will begin to function. Puberty occurs when a part of the brain called the hypothalamus begins to produce a hormone (gonadotropin) that has an effect on the testes and ovaries causing an increase sex hormone — estrogen in girls and testosterone in boys. Healthcare providers measure puberty in five stages in both girls and boys based on reproductive development.

In girls, the first sign of puberty is a breast bud, a small amount of firm, often tender tissue under the nipple. Girls then develop more tissue and shape to their breasts. Menstruation (periods) often starts in girls about 2 years after breast development begins, at an average age of 12 1/2. Pubic hair and body odor in girls are related more to the adrenal glands. This can start before any puberty has begun in normal girls.

In boys, the first sign of puberty is testicle growth, then penis and pubic hair growth. Boys develop facial hair, body odor, and lower voices during puberty. Some boys may develop some small breast buds during early puberty that is normal. They typically go away.

Other physical changes of puberty:

  • Growth spurts of bones and muscles and a rapid increase in height
  • Changes in body shape and size

Important Development Factors

Slow height growth (less than 2 inches a year) may be a sign of hormone deficiencies, including a rare condition called growth hormone deficiency. However, growth normally slows a little right before puberty is about to start.

Polycystic ovary syndrome (PCOS) can cause girls to skip menstrual periods. PCOS causes girls to make too much male hormone and leads to irregular periods, possible infertility, and metabolic problems. This condition should be evaluated by a healthcare provider.

Gender incongruence can also become noticeable during puberty. Gender incongruence is where one’s gender identity doesn’t match up with one’s body. For individuals with gender incongruence, experiencing pubertal body changes can contribute to emotional distress (called gender dysphoria.)

Delayed puberty is when a teen goes through body changes later than the usual age range. For girls, it can mean no breast development by age 13 or no menstrual periods by age 16. For boys, it means no enlargement of the testicles by age 14. Being a “late bloomer” which is a benign condition is the most common cause of delayed puberty. If the condition isn’t caused by a medical problem, then it usually doesn’t need treatment.

Precocious puberty is the appearance of testicular enlargement in boys and breast development in girls — in boys younger than age 9 and girls younger than 8 years of age. Precocious puberty affects about 1 – 2% of children in the United States.

Premature adrenarche refers to the development of pubic and armpit hair, acne, and adult body odor in boys and girls earlier than expected. These are thought to result from increased secretion of male hormones from the adrenal gland. The adrenal gland makes weak male hormones in both males and females. Although these changes usually occur together with the other signs of pubertal development such as testicular enlargement and breast development, the majority of these children do not require treatment as it is viewed as a normal variation.

Most likely, your child’s delayed or precocious puberty won’t need treatment. But, if you or your teen are concerned, it never hurts to see a doctor.

How is a child's delayed or precocious puberty diagnosed?

Your doctor will carefully evaluate your child’s medical history, including his or her birth history, sexual development, medications (including exposure to natural medicines, people using testosterone creams or lavender or tea tree oils in the house), illnesses, and emotional changes or injuries that could affect a child’s development. Your family history will also be reviewed including the pubertal development pattern of parents and siblings. He or she may also give your child a physical exam, schedule lab work, or take an X-ray of your child’s hand.

Should early or late puberty be treated?

Depending on the underlying condition causing your child’s early or late development, medication may or may not be needed. For children undergoing early pubertal development, your doctor may discuss whether the use of a medication to delay puberty would be needed. The rational for treatment of precocious puberty is based on 2 main considerations. 20% of adult height is attained during puberty and therefore untreated precocious puberty could result in stunted growth. Additionally, there may be psychological considerations for children maturing much faster than their peers. The majority of children with late puberty have a “late bloomer” pattern of growth called constitutional delay of growth and development. These children typically require no medical treatment. If a child has a delayed puberty arising from an inability of the body to make the needed hormones, a hormone replacement regimen is prescribed. This regimen will try to copy the normal pubertal timing. Some children will need to remain on these medications into adulthood.

Questions to ask your doctor

  • What should I tell my child about these physical changes?
  • Should I take my child to a pediatric endocrinologist?
  • What if my child is having a difficult time coping with these changes?
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