is described as '''delayed''' when a boy or girl has passed the usual age of onset of
Puberty with no physical or
Hormonal signs that it is beginning. Puberty may be delayed for several years and still occur normally, but delay of puberty may also occur due to
Undernutrition , many forms of systemic
Disease , or to defects of the
Reproductive System (
Hypogonadism ) or the body's responsiveness to
Sex Hormone s.
Puberty refers to the physical and hormonal changes which typically begin in early adolescence and lead to reproductive maturity and completion of growth. In girls the physical changes include growth of the
Breast s, development of
Pubic Hair , change in body shape, increased body hair, slightly increased facial hair, and onset of
Menstrual Periods (
Menarche ). In boys the physical changes include growth of the
Penis and
Testes ,
Pubic Hair , increased
Muscle mass and strength, and increased body and facial hair. These changes in both sexes are referred to as
Secondary Sex Characteristic s.
The body changes are triggered by rising levels of the
Sex Steroid s (
Androgen s and
Estrogen s). These arise from parallel hormonal processes termed "
Adrenarche " and "
Gonadarche ." Adrenarche refers to maturation of the
Adrenal Cortex with rising levels of adrenal androgens. These can produce early stages of
Pubic Hair , underarm hair, adult
Body Odor , and increased skin oiliness. This process is at least partly independent of gonadarche, which is an early part of central puberty, initiated by the
Central Nervous System and resulting in mature
Fertility . Gonadarche is the consequence of a cascade of events beginning with increased amplitude of
Gonadotropin-releasing Hormone from the
Hypothalamus , causing increased amplitude of
Gonadotropin pulses from the
Pituitary Gland , which in turn activate the hormone producing cells of the
Testes and
Ovaries .
Approximate mean ages for onset of various pubertal changes are as follows. Ages in parentheses are the approximate 3rd and 97th percentiles for attainment. For example, less than 3% of girls have not yet achieved
Thelarche by 13 years of age.
For North American and European girls
- Thelarche 10y5m (8y-13y)
- Pubarche 11y (8.5-13.5y)
- Growth spurt 10-12.5y
- Menarche 12.5y (10.5-14.5)
- Adult height reached 14.5y
For North American and European boys
- Testicular enlargement 11.5y (9.5-13.5y)
- Pubic hair 12y (10-14y)
- Growth spurt 12.5-15y
- Completion of growth 17.5
The sources of the data, and a fuller description of normal timing and sequence of pubertal events, as well as the
Hormonal changes that drive them, are provided in the principal article on
Puberty .
Obviously anyone who is later than average is late in the ordinary sense. There are three indications that pubertal delay may be due to an abnormal cause. The first is simply degree of lateness: although no recommended age of evaluation cleanly separates pathologic from physiologic delay, a delay of 2-3 years or more warrants evaluation.
- In girls, no breast development by 13 years, or no menarche by 3 years after breast development (or by 16).
- In boys, no testicular enlargement by 14 years.
The second indicator is discordance of development. In most children, puberty proceeds as a predictable series of changes in specific order. In children with ordinary constitutional delay, all aspects of physical maturation typically remain concordant but a few years later than average. If some aspects of physical development are delayed, and others are not, there is likely something wrong. For instance, in most girls, the beginning stages of breast development precede pubic hair. If a 12 year old girl were to reach
Tanner Stage 3 pubic hair for a year or more without breast development, it would be unusual enough to suggest an abnormality such as defective ovaries. Similarly, if a 13 year old boy had reached stage 3 or 4 pubic hair with testes that still remained prepubertal in size, it would be unusual and suggestive of a testicular abnormality.
The third indicator is the presence of clues to specific disorders of the
Reproductive System . For example,
Malnutrition or
Anorexia Nervosa severe enough to delay puberty will give other clues as well. Poor growth would suggest the possibility of
Hypopituitarism or
Turner Syndrome . Reduced sense of smell (hyposmia) suggests
Kallmann Syndrome .
Pediatric Endocrinologists are the physicians with the most training and experience evaluating delayed puberty.
A complete medical history, review of systems, growth pattern, and physical examination will reveal most of the systemic diseases and conditions capable of arresting development or delaying puberty, as well as providing clues to some of the recognizable
Syndrome s affecting the reproductive system.
An x-ray of the hand to assess
Bone Age usually reveals whether overall physical maturation has reached a point at which puberty should be occurring.
The most valuable blood tests are the
Gonadotropin s, because elevation confirms immediately a defect of the
Gonad s or deficiency of the
Sex Steroid s. In many instances, screening tests such as a
Complete Blood Count , general chemistry screens,
Thyroid tests, and
Urinalysis may be worthwhile.
More expensive and complicated tests, such as a
Karyotype or
Magnetic Resonance Imaging of the head, are usually obtained only when specific evidence suggests they may be useful.
If a child is healthy but simply late, reassurance and prediction based on the bone age can be provided. No other intervention is usually necessary. In more extreme cases of delay, or cases where the delay is more extremely distressing to the child, a low dose of testosterone or estrogen for a few months may bring the first reassuring changes of normal puberty.
If the delay is due to systemic disease or undernutrition, the therapeutic intervention is likely to focus mainly on those conditions.
If it becomes clear that there is a permanent defect of the reproductive system, treatment usually involves replacement of the appropriate hormones (
Testosterone for boys,
Estradiol and
Progesterone for girls).
