Menarche and voice change as indicators of the pubertal growth spurt.

Longitudinal data on adolescent growth in body height and on the occurrence of menarche in girls and voice change in boys have been colleced as part of a prospective study of the growth and development of 212 randomly selected Swedish urban children. The onset, peak and end of the pubertal growth spurt was defined on the unsmoothed incremental curve of height. The relationship in time between these events and menarche and voice changes was studied. Menarche occurred between 10.7 and 16.1 years (mean 13.1 years, S.D. = 1.09). No menstrual bleeding occurred before peak height velocity and all girls had the menarche before the end of the spurt. Clinically assessed voice change began between 11.5 and 16.5 years (mean 13.9 years, S.D. = 1.03). A voice with adult characteristics was observed between 12.5 and 17.5 years (mean 15.0 years, S.D. = 0.98). The duration of the voice change varied between less than one year and more than three years. When the voice change of a boy has begun, the growth spurt is in its most intensive phase. When the voice has acquired adult characteristics the growth rate has begun to decelerate.