Delayed puberty is defined as the absence of secondary sexual characteristics at age 13 in girls and 16 in boys (Chapters 11 and 12). It may result from: (i) a nonpathologic constitutional delay accompanying a growth delay; (ii) disorders of the hypothalamus or pituitary gland that result in inadequate gonadotropin secretion (hypogonadotropic hypogonadism); and (iii) disorders of the gonads that prevent adequate sex steroid secretion (hypergonadotropic hypogonadism) (Table 29.1). In girls, secondary sexual characteristics may develop without progression to menarche. This form of pubertal dysfunction and other causes of primary amenorrhoea are discussed in Chapter 30.

It is important to diagnose and treat delayed or absent puberty because: (i) serious underlying conditions may be present; (ii) abnormal persistence of a child-like phenotype has profound social implications for the teenager and young adult; (iii) prolonged absence of gonadal steroid exposure leads to osteopenia, a failure of normal bone formation. Osteopenia is associated with an increased risk of fractures in weight-bearing bones such as vertebrae, hips and long bones. Treatment of delayed or absent puberty aims to correct underlying disorders. Hormone replacement with estrogen/progesterone or testosterone is often required if hypogonadism is prolonged or age-appropriate sex steroid secretion patterns cannot be restored.

Constitutional pubertal delay

Pathologic causes of delayed puberty must be excluded before the diagnosis of constitutional pubertal delay can be considered. Constitutional pubertal delay is characterized by linear growth velocities and gonadotropin-releasing hormone (GnRH) secretory patterns that are appropriate for the individual’s bone age. In girls, it has been observed that puberty begins at a bone age of 12 years. Therefore, a 13-year-old girl who has a bone age of 11 and has not developed secondary sexual characteristics may have constitutional delay.