HYPOTHESIS: The onset age of puberty impacts on its progress, pubertal growth and transition to adulthood. METHODS: We analyzed prospectively collected data of 659 girls from 1991-2006, considering the onset of puberty (B2 and P2), menarche age [M]), its duration, transition to adulthood (M, B5 and P5) and pubertal growth. Data were divided into quartiles (Q) by B2 age, and we compared 1stQ (B2 age 8.95±0.03[SD]) with 4thQ (10.74±0.60y, P<.001; mean difference 1.79y) for puberty’s duration and completion parameters. RESULTS: 1stQ for B2 girls had their P2 at age 9.81±0.65 and 4thQ at 10.74±0.77y, resp.(P<.001, diff 0.92y), and M at 11.91±1.18 and 12.99±1.12y (P<.001; diff 1.08y). The duration from B2 to M was longer for B2-1stQ girls (2.95±1.19) than 4thQ (2.26±1.03, P<0.001; diff 0.69y). Completion of breast development (B5) was at age 13.96±0.96 and 14.40±0.84y for 1st and 4thQ, (P<0.001, diff 0.44 y). The duration B2 to B5 was longer in 1stQ girls (4.71±0.97y) than 4thQ (3.66±0.87y, P<0.001, diff 1.05y). During B2-B5, 1stQ girls grew more (24.8±5.5cm) than 4thQ (19.9±4.5cm, P<0.001), yet they reached similar final adult height of 164.5±6.4cm. The duration from M to B5 was comparable between 1st and 4thQ. CONCLUSIONS: Early thelarche predicts earlier pubarche >> earlier M, suggesting that B2 may not represent HPG maturation. Puberty duration difference is established by M, with no impact for the interval from M to adulthood. Parents may be reassured that early B2 girls within the normal range have longer puberty, comparable final height and M only three years later.
