The associations between left-hand digit ratio (2D:4D) and puberty characteristics among Chinese girls

The aim of this study was to analyse the associations of left-hand digit ratio (2D:4D), digit length and puberty characteristics to show the role of prenatal hormones in development among Chinese girls.

A total of 318 Chinese girls aged 8-15 years were recruited using a stratified cluster sampling method. The index finger (2D), ring finger (4D) of the left hand, oestradiol and testosterone were measured, and age at menarche (AAM), breast (high and low) and pubic hair (high and low) development were recorded.

Girls who had experienced menarche had longer left digits (2D and 4D) and higher oestradiol, testosterone than those who had not. The high breast group had longer digits (2D and 4D), and higher oestradiol than the low breast group. With regard to pubic hair development, the high group had high 2D:4D, longer 2D and higher oestradiol, testosterone than the low group. After adjusting for oestradiol and testosterone, 4D length was positively related to occurrence of menarche. In addition, 2D and 2D:4D were significantly correlated with pubic hair development after adjusting for oestradiol, respectively.

Prenatal hormone level may be related to the development of puberty characteristics among Chinese girls.