Objective: To evaluate prospectively pubertal and predicted adult height progression until final height (FH) or near FH in girls with apparent idiopathic precocious puberty who were not treated.
Study design: The decision not to treat at the time of initial evaluation was based on evidence of slowly progressive puberty as shown by bone age (BA) advancement <2 years above the chronologic age, whatever the hypothalamic pituitary ovarian axis activation, or no evidence of hypothalamic pituitary ovarian axis activation, whatever the BA advancement. During follow-up, patients who showed a significant decrease in predicted FH were treated with gonadotropin-releasing hormone agonist.
Results: Twenty-six girls with idiopathic precocious puberty were studied at a mean chronologic age of 7.4 +/- 0.9 years during a follow-up period of 6.6 +/- 2.2 years until FH or near FH. During the first 2 years of follow-up, most of the patients (group 1, n = 17; 65% of the cases) showed no substantial changes in predicted FH. They never required treatment, and menarche occurred at a mean chronologic age of 11.9 +/- 0.6 years. Their mean FH (or near FH) at 160.7 +/- 5.7 cm was close to their target height (161.3 +/- 4.7 cm). On the other hand, after a mean follow-up period of 1.4 +/- 0.8 years, 9 patients (group 2) had acceleration of bone maturation and deterioration of their predicted FH (from 162.1 +/- 6. 2 cm to 155.3 +/- 5.6 cm; P <.01), which was at that time significantly lower than their target height (P <.05) (mean target height = 159.8 +/- 4.6 cm). They received a gonadotropin-releasing hormone agonist for 2.1 +/- 0.7 years, resulting in a restoration of growth prognosis (mean FH or near FH = 160.2 +/- 6.7 cm).
Conclusions: This study demonstrates that not all patients with apparent idiopathic precocious puberty require medical treatment, notably when there is no evidence of hypothalamo-pituitary ovarian activation or no significantly advanced BA to impair height potential. Most show a slowly progressing puberty. However, careful follow-up of these patients is necessary up to at least 9 years of age, because until then height prediction may deteriorate, necessitating gonadotropin-releasing hormone agonist treatment in one third of the cases.