Growth pattern and final height after cessation of gonadotropin-suppressive therapy in girls with central sexual precocity.

OBJECTIVE: The objective of the study was to determine whether height gain after discontinuation of gonadotropin-suppressive (GnRHa) therapy differs in girls with sexual precocity diagnosed at various ages and assess its influence on final height (FHt) outcome.

DESIGN: We compared data on post-GnRHa treatment course and FHt of 115 girls [22 diagnosed before chronological age of 6 yr; 38 between ages 6 and 8 yr; and 55 early fast puberty (EFP) between ages 8 and 9 yr] treated with GnRHa from Tanner stage 2-3 to chronological age 11-12 yr and bone age 12-12.5 yr.

RESULTS: Despite comparable bone age at cessation of treatment, similar time to resumption of puberty (0.6 +/- 0.7, 0.5 +/- 0.7, and 0.5 +/- 0.7 yr), and age at menarche (12.6 +/- 0.5, 12.6 +/- 0.6, and 12.7 +/- 0.9 yr), height gain from cessation of therapy to FHt was greater and time to epiphyseal fusion was longer in the younger central precocious puberty (CPP) than in the older CPP (P < 0.05) and EFP (P < 0.001) groups. The percentage of residual growth predicted at discontinuation of treatment was achieved only by the younger CPP (6.6 +/- 1.6% vs. 6.7 +/- 1.6%), whereas in older CPP and EFP, it was significantly lower (6.2 +/- 1.6% vs. 4.6 +/- 2.7% and 6.3 +/- 1.5% vs. 3.6 +/- 1.5%, respectively). FHt of these two groups was compromised, compared with FHt predicted at discontinuation of treatment (P < 0.01 and P < 0.001, respectively).

CONCLUSIONS: Girls with sexual precocity diagnosed after the age of 6 yr exhibit earlier epiphyseal fusion with diminished posttreatment height gain and compromised FHt. Because recovery of gonadal axis was similar in all girls, differences were probably due to pretreatment intrinsic changes in the growth plate. Prediction of residual growth at discontinuation of treatment is unreliable in these girls.