[Influence of birthweight on the onset and progression of puberty and final height in precocious pubarche].

Background: Girls born small for gestational age (SGA), with a birth weight < 1.5 SDS, are at increased risk of early onset and rapid progression of puberty, with reduced final height. In contrast, idiopathic precocious pubarche (PP) does not seem have negative effects on the onset of puberty or final height.
Objective: We evaluated the relationship between birthweight, the onset and progression of puberty and final height in girls with PP.
Methods: We performed a retrospective study of girls at the onset of puberty with a history of PP (pubic hair before the age of 8 years).
Results: A total of 124 girls (37 SGA) were investigated; 61 had presented menarche and 44 had reached final height. The mean ( SD) age was 6.8 0.8 years at pubarche, 9.5 0.9 at the onset of puberty and 11.7 6 0.9 at menarche. No significant differences were found in the correlation between birth weight expressed in SDS and age at presentation of pubarche, bone age at presentation of pubarche, age at telarche or age at menarche. A positive correlation was found between birthweight and height at pubarche, telarche, and menarche and final height. These data suggest that pubertal progression is faster in SGA girls. All patients reached the familial target height but only those with an appropriate birthweight were taller than their mothers.
Conclusions: PP does not seem to modify age of onset or progression of puberty or final height in girls with adequate birth weight. In contrast, in SGA girls, PP is associated with faster puberal development and shorter final height. Therefore, SGA girls with PP require periodic monitoring.