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Puberty can be considered a continuous process in which the hypothalamic-pituitary-gonadal axis develops from the infantile stages to maturity. The physical development of puberty can be denoted in an objective manner by sexual maturation ratings (SMRs), commonly referred to as Tanner stages. Staging provides an objective, consistent description of physical development, which allows recognition of precocious or delayed puberty or problems with the tempo of pubertal development. In girls, breast development and pubic hair development are usually, but not always coordinated, and should be documented separately. Similarly, in boys, genital development and pubic hair development are typically synchronous but should be described independently.
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Findings used for Tanner staging among girls are shown in Figure 533-1A. An increase in growth velocity is one of the first signs of female pubertal onset, but breast development is the first sign noted by most examiners. Breast development among girls can start unilaterally, and asymmetric breast development is not abnormal in early puberty. Breast size and shape are influenced by genetic and nutritional factors, with areolar changes occurring in predictable sequence. The appearance of the vaginal mucosa changes from a prepubertal reddish color to a duller pinkish hue as a result of cornification of the vaginal epithelium, which reflects a change in its histology due to the effect of estrogen. The labia minora and majora thicken, uterine volume and ovarian size increase, and a whitish or clear vaginal discharge occurs prior to menarche. Axillary hair appears and thickens and axillary odor develops as signs of adrenarche, the awakening of adrenal androgen secretion. It is important to note that both boys and girls can achieve fertility before physical maturity is reached.
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