Table 1.
Age References for Breast Development, Pubic Hair and Menarche: Median and Distribution (–2, –1, 1, 2 SD) of the Age (in Years) at Attainment of the Specified Stage
| Generalized Additive Model Age at Attainment | Probit | |||||
|---|---|---|---|---|---|---|
| Pubertal marker | –2 SD | –1 SD | Median | 1 SD | 2 SD | Mean (SD) age |
| Breast (ultrasound) | ||||||
| US B1 | NA | 5.6a | 8.3 | 10.7 | 12.4 | 8.3 (2.2) |
| S B2 | 7.7 | 8.9 | 10.2 | 11.5 | 12.8 | 10.2 (1.3) |
| US B3 | 9.1 | 10.3 | 11.5 | 12.7 | 13.9 | 11.5 (1.2) |
| US B4 | 10.4 | 11.3 | 12.3 | 13.9 | NA | 12.7 (1.5) |
| US B5 | 11.3 | 12.7 | 15.9 | NA | NA | 15.3 (2.3) |
| Breast (Tanner) | ||||||
| B2 | 8.0 | 9.2 | 10.4 | 11.6 | 12.7 | 10.4 (1.2) |
| B3 | 9.5 | 10.4 | 11.4 | 12.5 | 13.8 | 11.5 (1.1) |
| B4 | 10.7 | 11.6 | 12.5 | 13.8 | NA | 12.8 (1.3) |
| B5 | 11.1 | 12.3 | 14.7 | NA | NA | 14.8 (2.2) |
| Pubic Hair (Tanner) | ||||||
| PH2 | 8.5 | 9.7 | 10.9 | 12.1 | 13.3 | 10.9 (1.2) |
| PH3 | 9.7 | 10.9 | 11.9 | 12.9 | 13.7 | 11.9 (1.1) |
| PH4 | 10.5 | 11.8 | 13.1 | 14.4 | 15.7 | 13.1 (1.3) |
| PH5 | 11.4 | 13.0 | 15.1 | NA | NA | 15.1 (1.9) |
| Menarche | 11.0 | 11.7 | 12.7 | 14.1 | 16.2 | 12.9 (1.2) |
Distribution of age at entry in consecutive stages of breast development measured with ultrasound (US B; n = 696), breast development according to Tanner B (n = 700), Pubic hair (PH) according to Tanner (n = 372) and menarche (n = 643) in 6- to 16-year-old healthy girls in Bergen, Norway. Median age and ±1 or 2 reference limits were estimated with nonparametric generalized additive models. Mean (SD) ages were estimated with probit regression.
Abbreviations: B, breast; NA, not applicable (outside the data range); PH, pubic hair; SD, standard deviation; US B, ultrasound-based breast stage.
aExtrapolated age that falls just below the data range.