Precocious and delayed puberty

Definition

• Precocious puberty denotes the onset of secondary sexual characteristics in girls before the age of 8.
• Delayed puberty in girls is present if breast development has not begun by the age of 13, more than 3 years elapse between thelarche and menarche, or menarche has not occurred by the age of 15; the cut-offs for the last two criteria are not defined uniformly in the literature.

Classification

• Precocious puberty is divided into the more common central, gonadotrophin-dependent form and a peripheral, gonadotrophin-independent form; premature thelarche and premature adrenarche are benign, non-progressive variants.
• Delayed puberty is divided into constitutional delay, functional and permanent hypogonadotrophic hypogonadism, and hypergonadotrophic hypogonadism.

Occurrence & epidemiology

Epidemiology

• True precocious puberty affects about 0.2% of girls.
• In recent decades, puberty has started earlier, especially in girls, probably owing to increasing childhood obesity and environmental factors.

Aetiopathogenesis

Aetiology and pathogenesis

• In most girls with central precocious puberty no specific cause can be identified; intracranial lesions such as hamartomas or other tumours of the hypothalamic region are uncommon.
• Peripheral forms result from sex hormones from the gonads, adrenals or exogenous sources; oestrogenic effects are most commonly due to follicular ovarian cysts, less often to granulosa-theca cell tumours or McCune-Albright syndrome, and androgen excess most commonly to congenital adrenal hyperplasia with 21-hydroxylase deficiency.
• Causes of delayed puberty include chronic illness, undernutrition and eating disorders, excessive physical activity, Kallmann syndrome with hyposmia or anosmia, and chromosomal disorders such as Turner syndrome.

Clinical features

• In precocious puberty, an early growth spurt leads to reduced adult height through premature epiphyseal closure; psychosocial problems may also occur.

Diagnosis

• A pubertal morning LH level measured with a high-sensitivity assay, or a pubertal LH response to stimulation testing, indicates a central form.
• A radiograph of the left hand shows accelerated skeletal maturation; brain MRI serves to exclude intracranial causes.
• In delayed puberty, raised gonadotrophins point to primary gonadal failure; bone age and, if gonadotrophins are raised, karyotyping, for example for Turner syndrome, complete the work-up.

Keep learning in the app

Further reading (selection)

1. StatPearls: Precocious Puberty (NCBI Bookshelf)
2. MSD Manual Professional: Precocious Puberty
3. MSD Manual Professional: Delayed Puberty

Cross-references