TRIP

Delayed Puberty

Now@NEJM, 2012

The latest article in our Clinical Practice review series is, Puberty is considered delayed when it has not yet occurred at an age that is 2 to 2.5 SD later than average (traditionally, 14 years in boys and 13 years in girls).
It requires an intact hypothalamic-pituitary-gonadal (HPG) axis and is heralded by the reemergence of gonadotropin-releasing hormone (GnRH) secretion from its relative quiescence during childhood.
GnRH stimulates the secretion of luteinizing hormone and follicle-stimulating hormone (FSH), which then stimulate gonadal maturation and sex-steroid production.
Much is known about components of the HPG axis, but the factors that trigger pubertal onset remain elusive.
It is not understood why one boy begins puberty at the age of 10 years and another at the age of 14 years.
Delayed puberty is defined as the absence of testicular enlargement in boys or breast development in girls at an age that is 2 to 2.5 SD later than the population mean (traditionally, the age of 14 years in boys and 13 years in girls).
However, because of a downward trend in pubertal timing in the United States and other countries and differences in pubertal timing among racial and ethnic groups, some observers have advocated for updated definitions with younger age cutoffs for the general population or perhaps for particular countries or racial or ethnic groups.
Development of pubic hair is usually not considered in the definition because pubarche may result from maturation of the adrenal glands (adrenarche), and the onset of pubic hair can be independent of HPG-axis activation.
• What is the most common etiology of delayed puberty, and what is the differential diagnosis?
Delayed puberty usually represents an extreme of the normal spectrum of pubertal timing, a developmental pattern referred to as constitutional delay of growth and puberty (CDGP).
Although CDGP represents the single most common cause of delayed puberty in both sexes, it can be diagnosed only after underlying conditions have been ruled out.