Reference range of bone age-based uterine volume in growing girls

Uterine volume (UV) and bone age (BA) are important determinants for evaluating the pubertal status of growing girls. However, the correlation between these two parameters in growing children has not yet been fully investigated.

This retrospective observational study collected data from girls aged 1-14 years who were classified into precocious puberty (PP) and normal puberty (NP) for subgroup analysis. The demographic data, BA, and UV were thoroughly analyzed to elucidate their associations.

A total of 542 girls were enrolled in the study from 2013 to 2022. The PP group had a slightly higher height-SDS (p = 0.175) and significantly higher weight-SDS (p < 0.019) compared with the NP group. Although the inflection point of increased mean UV was the same at the age of 9 in PP (8 yrs: 3.15 cm³; 9 yrs: 5.7 cm³) and NP groups (8 yrs: 2.98 cm³; 9 yrs: 6.06 cm³), a dramatically increasing trend of UV was noticed in PP girls. Compared with chronological age (CA), BA showed a more significant correlation with UV (r²=0.491 in PP, r²=0.515 in NP, both p < 0.01).

This study provides the reference ranges of UV, which are not only based on CA and BA but which also considered both PP and NP statuses. Different references of UV are recommended when evaluating growing children in view of diverse onset ages of puberty.