The start of breast development and age at menarche in South African black females.

Age at the start of breast development and at menarche are important maturity indicators in adolescent females. Breast development is usually the first event of puberty and menarche virtually the last. Irregularities in the age of the subject at their appearance can denote a lack of synchronisation between pubertal events, which, in turn, may indicate hormonal or psychosocial disturbance. Data are presented on the age of occurrence of breast development, according to Tanner's criteria, and age at menarche for urban and rural South African black females. In addition published reports are reviewed to determine whether there is a pattern of change in these ages. Breast development seems to be fairly stable, occurring in girls between the ages of 10.5 years and 11.5 years. Age at menarche appears to have decreased over the last 40 years in children from both urban and rural environments. Girls from rural areas have a delay of about 1.5 years in both pubertal events.