Early onset of puberty in young girls: an Italian cross-sectional study

International literature and clinical practice have referred to Marshall and Tanner data to define the physiological age at onset of puberty. A study in the United States (1997) showed an anticipation in pubertal onset, whereas several European studies did not confirm this trend.

To describe the onset of secondary sexual characteristics in a large Italian population of girls and to compare it to reference literature data.

A cross-sectional study on 7311 2-14-yr-old girls who spontaneously requested a clinical evaluation for routine health check-up or acute illness by family pediatrician's offices in a northern Italian region (Lombardy), between September 2005 and November 2006. Trained family pediatricians performed a complete physical examination; pubertal status was evaluated following Tanner's criteria; breast development was assessed by palpation.

Mean age of thelarche (B2), pubarche (PH2), menarche were 9.75, 10.09, and 12.49 yr, respectively. The prevalence of B2 and PH2 at ages 7-7.99 was 5.9% and 5.6%, respectively, at ages 8-8.99 was 15.5% and 13.8%, respectively. Mean time lapse from B2 to B3 and B2 to menarche was 1.46 and 2.74 yr, respectively. Mean age at menarche of our population and their respective mothers was almost identical.

Our population presented earlier clinical signs of pubertal development than those defined by Marshall and Tanner. Mean age of menarche was not different in comparison to the previous generation. A different progression of pubertal development was found, in which the shift to B3 may have more clinical relevance.