EARLY MENARCHE

The average age of menarche is 13 years, and the start of periods before the age of 9 years, as in this case, is classified as precocious puberty. In normal puberty, girls tend to start breast bud development from 9–13 years, start pubic hair growth from 10–14 years and menarche starts at 11–15 years. An increased rate of growth starts at 11–12 years and growth finishes at around 15 years. When these changes occur early but in the normal sequence, the precocious puberty is usually of no significant consequence and termed constitutional early development. This is often familial. However, if it occurs very early or in an abnormal sequence, a pathological cause is more likely

Problems of precocious puberty

• Growth: although the growth spurt starts early in precocious puberty, growth also stops prematurely (premature epiphyseal closure) and therefore girls with precocious puberty are at risk of having a reduced final stature if untreated.

• Embarrassment: early secondary sexual characteristics and the onset of periods can be very difficult for a girl to deal with at a young age.

• Social interaction: difficulties can occur when people who do not know the child’s chronological age assume a level of intellectual and emotional maturity according to the child’s physical maturity (apparent age).

Investigation Gonadotrophins, prolactin and thyroid hormones should be checked to confirm that they correlate with normal pubertal levels. Computerized tomography (CT) or magnetic resonance imaging (MRI) may be necessary for visualization of the pituitary stalk. Abdominopelvic ultrasound will rule out an ovarian or adrenal tumour. Bone scan will determine biological bone age to ascertain whether pituitary suppression is indicated.

Management

As the changes in this girl seem to be in a normal sequence and she is within two years of the normal age of menarche she can be managed expectantly. However, if the changes had started at a younger age, pituitary suppression should be started with gonadotrophin-releasing hormone analogues, to delay the growth spurt and thus maintain full final height.

KEY POINTS

• Over 90 per cent of girls with precocious puberty have constitutional (idiopathic) precocious puberty with no pathological cause, but an abnormal sequence of pubertal development or very early puberty should trigger further investigation.

• The major problems of precocious puberty are short final stature and social embarassment.