Delayed puberty is when the usual age of onset of puberty has passed, and there is no physical/hormonal signs that it is beginning.

• In girls:
  • Thelarche (breast development), is by 10.5yo
  • Pubarche (pubic hair), by 11yo
  • Growth spurt, by 11.5yo
  • Menarche (first menstrual bleed), by 12.5yo
  • Adult height by 15yo, by 15.5yo
• In boys:
  • Gonadarche (testicular enlargement), is by 11.5yo
  • Pubarche (pubic hair), by 12yo
  • Growth spurt, by 17yo
  • Adult height, by 17yo

• Constitutional delay, which is a variation of healthy physical development, where puberty is delayed for sveral years and still considered normal
• In females, high levels of physical exertion (e.g. from being athletic)
• Malnutrition (e.g. anorexia nervosa, zinc deficiency)
• Systemic disease (e.g. IBD, chronic renal failure)
• HPG axis:
  • Pituitary defect (e.g. hypopituitarism)
  • Gonadal defects (e.g. Turner syndrome, Klinefelter syndrome, testicular failure, Mullerian agenesis)
• Other endocrine disorders (e.g. hypothyroidism, Cushing's syndrome)
• Genetic disorders (cystic fibrosis, Turner syndrome, Klinefelter syndrome)
• Defects to the body's responsiveness to sex hormones

• Degree of lateness, where a delay of 2-3 years or more warrants evaluation. This would thus include:
  • In girls, no breast development by 13yo, or no menarche by 3 years after breast development (i.e. 16yo)
  • In boys, no testicular enlargement by 14yo, or delay in development for 5 years or more after onset of testicular enlargement (i.e. 19yo)
• Discordance of development, where puberty doesn't proceed in the expected specific order
• Indications of specific reproductive disorders, including:
  • Malnutrition/anorexia nervosa, severe enough to delay puberty
  • Poor growth, suggests hypopituitarism or Turner syndrome