Puberty and Precocious Puberty

What are normal puberty, precocious puberty, and delayed puberty?

Normal Puberty

The time in one's life when sexual maturity takes place is known as puberty. The physical changes that mark puberty typically begin in girls between ages 8 and 13 and in boys between ages 9 and 14.

Precocious Puberty

Precocious puberty is a condition that occurs when sexual maturity begins earlier than normal. Precocious (meaning prematurely developed) puberty begins before age 8 for girls and before age 9 for boys.

Children affected by precocious puberty may experience problems such as¹:

• Failure to reach their full height because their growth halts too soon
• Psychological and social problems, such as anxiety over being "different" from their peers. However, many children do not experience major psychological or social problems, particularly when the onset of puberty is only slightly early.

Delayed Puberty

Delayed puberty is the term for a condition in which the body's timing for sexual maturity is later than the normal range of ages.

Many children with delayed puberty will eventually go through an otherwise normal puberty, just at a late age. Other children have a long-lasting condition known as hypogonadism (pronounced HI-poe-GO-nad-iz-uhm) in which the sex glands (the testes in men and the ovaries in women) produce few or no hormones. For example, hypogonadism can occur in girls with Turner syndrome or in individuals with hypogonadotropic (pronounced HI-po-GO-nah-doe-TROH-pik) hypogonadism, which occurs when the hypothalamus (pronounced HI-po-THAL-uh-muss) produces little to no gonadotropin-releasing hormone (pronounced goh-nad-uh-TROH-pin) (GnRH).

Normal Puberty

In Girls

The signs of puberty include:

• Growth of pubic and other body hair
• Growth spurt
• Breast development
• Onset of menstruation (after puberty is well advanced)
• Acne

In Boys

The signs of puberty include¹:

• Growth of pubic hair, other body hair, and facial hair
• Enlargement of testicles and penis
• Muscle growth
• Growth spurt
• Acne
• Deepening of the voice

Precocious Puberty

The symptoms of precocious puberty are similar to the signs of normal puberty but they manifest earlier—before the age of 8 in girls and before age 9 in boys.

Delayed Puberty

Delayed puberty is characterized by the lack of onset of puberty within the normal range of ages.

Precocious puberty is rare, meaning it affects about 1% or less of the U.S. population.¹ Many more girls are affected than boys.

One study suggests that African American girls have some early breast development or some early pubic hair more often than white girls or Hispanic girls. There is a greater chance of being affected by precocious puberty² if a child is:

• Female
• African American
• Obese

Normal Puberty

Puberty is the body's natural process of sexual maturation. Puberty's trigger lies in a small part of the brain called the hypothalamus, a gland that secretes gonadotropin-releasing hormone (GnRH). GnRH stimulates the pituitary gland, a pea-sized organ connected to the bottom of the hypothalamus, to emit two hormones: luteinizing (pronounced LOO-tee-uh-nize-ing) hormone (LH) and follicle-stimulating hormone (FSH). These two hormones signal the female and male sex organs (ovaries and testes, respectively) to begin releasing the appropriate sex hormones, including estrogens and testosterone, which launch the other signs of puberty in the body.¹

Precocious Puberty

In the majority of cases of precocious puberty, no underlying cause can be identified. When a cause cannot be identified, the condition is called idiopathic precocious puberty.

Sometimes the cause is an abnormality involving the brain. In other children, the signs of puberty occur because of a problem such as a tumor or genetic abnormality in the ovaries, testes, or adrenal glands, causing overproduction of sex hormones.

Precocious puberty can be divided into two categories, depending on where in the body the abnormality occurs—central precocious puberty and peripheral precocious puberty.

• Central Precocious Puberty
  This type of early puberty, also known as gonadotropin-dependent precocious puberty, occurs when the abnormality is located in the brain. The brain signals the pituitary gland to begin puberty at an early age. Central precocious puberty is the most common form of precocious puberty and affects many more girls than boys. The causes of central precocious puberty include:
  • Brain tumors
  • Prior radiation to the brain
  • Prior infection of the brain
  • Other brain abnormalities

• Peripheral Precocious Puberty
  This form of early puberty is also called gonadotropin-independent precocious puberty. In peripheral precocious puberty, the abnormality is not in the brain but in the testicles, ovaries, or adrenal glands, causing overproduction of sex hormones, like testosterone and estrogens. Peripheral precocious puberty may be caused by²:
  • Tumors of the ovary, testis, or adrenal gland
  • In boys, tumors that secrete a hormone called hCG, or human chorionic gonadotropin (pronounced kawr-ee-ON-ik goh-nad-uh-TROH-pin)
  • Certain rare genetic syndromes, such as McCune-Albright syndrome or familial male precocious puberty
  • Severe hypothyroidism, in which the thyroid gland secretes abnormally low levels of hormones
  • Disorders of the adrenal gland, such as congenital adrenal hyperplasia
  • Exposure of the child to medicines or creams that contain estrogens or androgens

Delayed Puberty

Many children with delayed puberty will eventually go through an otherwise normal puberty, just at a late age. Sometimes, this delay occurs because the child is just maturing more slowly than average, a condition called constitutional delay of puberty. This condition often runs in families.

Puberty can be delayed in children who have not gotten proper nutrition due to long-term illnesses. Also, some young girls who undergo intense physical training for a sport, such as running or gymnastics, start puberty later than normal.³

In other cases, the delay in puberty is not just due to slow maturation but occurs because the child has a long-term medical condition known as hypogonadism (pronounced HI-poe-GO-nad-iz-uhm), in which the sex glands (the testes in men and the ovaries in women) produce few or no hormones. Hypogonadism can be divided into two categories: secondary hypogonadism and primary hypogonadism.

• Secondary hypogonadism (also known as central hypogonadism or hypogonadotropic hypogonadism), is caused by a problem with the pituitary gland or hypothalamus (part of the brain). In secondary hypogonadism, the hypothalamus and the pituitary gland fail to signal the gonads to properly release sex hormones. Causes of secondary hypogonadism include⁴:
  • Kallmann syndrome, a genetic problem that also diminishes the sense of smell
  • Isolated hypogonadotropic hypogonadism, a genetic condition that only affects sexual development but not the sense of smell
  • Prior radiation, trauma, surgery, or other injury to the brain or pituitary
  • Tumors of the brain or pituitary
• In primary hypogonadism, the problem lies in the ovaries or testes, which fail to make sex hormones normally. Some causes include⁴:
  • Genetic disorders, especially Turner syndrome (in women) and Klinefelter syndrome (in men)
  • Certain autoimmune disorders
  • Developmental disorders
  • Radiation or chemotherapy
  • Infection

To identify whether a child is entering puberty, a pediatrician (a physician specializing in the treatment of children) will carefully examine the following:

• In girls, the growth of pubic hair and breasts
• In boys, the increase in size of the testicles and penis and the growth of pubic hair

The pediatrician will compare what he or she finds against the Tanner scale, a 5-point scale that gauges the extent of puberty development in children.^1,2

Precocious Puberty

After giving a child a complete physical examination and analyzing his or her medical history, a healthcare provider may perform tests to diagnose precocious puberty, including³:

• A blood test to check the level of hormones, such as the gonadotropins (luteinizing hormone [LH] and follicle-stimulating hormone [FSH]), estradiol, testosterone, dehydroepiandrosterone sulfate (DHEAS), and thyroid hormones
• A gonadotropin-releasing hormone agonist (GnRHa) stimulation test, which can tell whether a child's precocious puberty is gonadotropin-dependent or gonadotropin-independent
• Measuring blood 17-hydroxyprogesterone to test for congenital adrenal hyperplasia
• A "bone age" X­ray to determine if bones are growing at a normal rate

The healthcare provider may also use imaging techniques to rule out a tumor or other organ abnormality as a cause. These imaging methods may include:

• Ultrasound (sonography) to examine the gonads. An ultrasound painlessly creates an image on a computer screen of blood vessels and tissues, allowing a healthcare provider to monitor organs and blood flow in real time
• An MRI (magnetic resonance imaging) scan of the brain and pituitary gland using an instrument that produces detailed images of organs and bodily structures

Delayed Puberty

To diagnose hypogonadotropic hypogonadism, a healthcare provider may prescribe these tests ³:

• Blood tests to measure hormone levels
• Blood tests to measure if the pituitary gland can correctly respond to GnRH
• An MRI of the brain and pituitary gland

Precocious Puberty

There are a number of reasons to treat precocious puberty.¹

Treatment for precocious puberty can help stop puberty until the child is closer to the normal time for sexual development. One reason to consider treating precocious puberty is that rapid growth and bone maturation, caused by precocious puberty, can prevent a child from reaching his or her full height potential. Children grow rapidly in height during puberty and reach their final adult height after puberty. Children who go through puberty too early may not reach their full adult height potential because their growth stops too soon.

Another reason to consider treating precocious puberty is that a young child may not be psychologically ready for the physical and hormonal changes that occur in puberty.

However, not all children with precocious puberty require treatment, particularly if the onset of puberty is only slightly early. The goal of treatment is to prevent the production of sex hormones to prevent the early halt of growth, short stature in adulthood, emotional effects, social problems, and problems with libido (especially in boys).

If precocious puberty is caused by a specific medical problem, treating the underlying problem can often stop the progression of precocious puberty. In addition, precocious puberty can often be stopped by medical treatment to block the hormones that cause puberty. For example, medications called gonadotropin-releasing hormone agonists (GnRHa) are used to treat central precocious puberty. These medications, some of which are injected, suppress production of luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

Delayed Puberty

With delayed puberty or hypogonadism, treatment varies with the origin of the problem but may involve²:

• In males, testosterone injections, skin patches, or gel
• In females, estrogen and/or progesterone given as pills or skin patches