Delayed puberty is almost always due to physiologic exaggeration of the prolongation of puberty timing; a condition called constitutional delay of growth and puberty (CDGP). Other forms of delayed puberty include hypergonadotropic hypogonadism, permanent hypogonadotropic hypogonadism, and functional hypogonadotropic hypogonadism.

• Delayed puberty may be classified according to etiology into 4 subtypes which includes:^[1]
  • Constitutional delay of growth and puberty (CDGP)
  • Hypergonadotropic hypogonadism
  • Permanent hypogonadotropic hypogonadism
  • Functional hypogonadotropic hypogonadism
• The most common subtype of delayed puberty, constitutional delay of growth and puberty (CDGP), has no pathological etiology and is completely physiologic.
• Other subtypes of delayed puberty are classified upon the serum levels of sex hormones and also gonadotropins.
• The complete classification of delayed puberty is as follows:

Delayed puberty classification

LH, FSH, and GnRH plasma level

Normal

Abnormal

Constitutional delay of growth and puberty (CDGP)

LH and FSH increased GnRH increased

LH and FSH decreased GnRH decreased

LH and FSH decreased GnRH decreased (transient)

Hypergonadotropic hypogonadism (primary hypogonadism)

Permanent hypogonadotropic hypogonadism (secondary hypogonadism)

Transient hypogonadotropic hypogonadism (functional hypogonadism)

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