Puberty

September 23, 2011

Puberty is a dynamic period of development characterized by maturation of the genital organs, rapid changes in body size, shape, and composition, and the emergence of secondary sex characteristics. It marks the first time that adolescents are capable of sexual reproduction. Pubertal development is influenced by a wide array of biological and environmental variables and marked by substantial alterations in mood and behavior. Variations may be associated with several factors, including but not limited to ethnic background, nutrition, exercise, and body weight. Physiological changes that occur during puberty may have important long-term implications for women’s health. We close with a set of recommendations for future research and strategies to foster healthy adolescent development among health care providers.

BIOLOGICAL PROCESSES

The age of onset of puberty is earlier for girls than for boys and varies anywhere from 9 to 13 years. One of the hallmarks of puberty is the growth spurt accompanied by significant weight gain. The sequence of biological events that occur during puberty encompass a broad spectrum of cellular and somatic changes initiated by the hypothalamus and affecting the pituitary gland, both structures in the brain. The hypothalamus stimulates the pituitary gland to produce the gonadotropin-releasing hormone (GnRH). GnRH causes the hormones estrogen and testosterone to be released followed by the release of the growth hormone (GH) by the pituitary gland. This process begins a cascade of events where the internal sex organs (e.g., ovaries) increase in size, followed by the development of the breast buds. Next there is an increase in body hair on the legs, under the arms, and in the pubic region. As the levels of estrogen and testosterone steadily increase, there is an increase in body weight and height, followed by a widening of the hips. The last event of pubertal development for girls is usually the onset of menstruation, or menarche (see Menarche). Once menarche is achieved, changes in height and weight begin to slow down and within a short period of time, the young girl has reached her adult height and achieved reproductive maturity. Although there is some variation in the timing of specific stages, most adolescents follow the same sequence of events except under unusual circumstances such as malnutrition or excessive exercise.

The onset of puberty can begin at any time between age 9 and 13 to be considered within the normal range, but several studies have examined the effects of early and late puberty on girls. In general, girls who mature at the same time as their peers or later than their peers fare much better than those who mature before their peers. Girls who reach puberty before age 11 are defined as early maturers, although this classification may vary according to context and ethnicity. The definition of early maturation is generally relative to one’s peers; if the girl reaches puberty before her peers, she is considered an early maturer. Early maturation in girls has been associated with higher rates of mental health problems such as anxiety, depression, and eating disorders. Early maturation is also related to elevated rates of high-risk behaviors such as smoking, drug use, delinquent behaviors, and early sexual intercourse. The mechanism by which early maturation leads to these negative outcomes is unclear. Some research implicates increased testosterone levels whereas other data suggest that girls who mature early face a host of expectations associated with adulthood for which they are unprepared. The lack of congruity between girls’ physically mature appearance and psychological immaturity has been postulated as one explanation for these girls’ poor adjustment. Moreover, early maturing girls’ first boyfriends are usually 2-3 years older than them, thereby increasing their exposure to higher risk activities.

ENVIRONMENTAL INFLUENCES

Recent trends in adolescent development (e.g., height, timing of puberty) provide evidence that environmental factors influence pubertal processes. For example, girls are maturing earlier today than ever before, with the onset of public hair and breast development reported at 8.9 years for African Americans and 10.5 among Caucasians, respectively. Research documents the important role of nutrition and exercise in pubertal development. Specifically, undernutrition is related to later age at menarche and delayed pubertal maturation, whereas obesity is associated with early sexual maturation. Similarly, moderate physical activity or exercise has been linked to cardiovascular benefits and favorable body changes, but excessive physical activity such as the kind often required by some sports (e.g., gymnastics, wrestling) negatively affects adolescent development by slowing growth and maturation.

IMPLICATIONS FOR WOMEN’S HEALTH IN ADULTHOOD

Several studies indicate that certain physiological processes during puberty may have implications for women’s health in adulthood, including the timing of puberty, the development of bone density, and the strength of immune functioning. The timing of puberty has consequences for estrogen exposure; earlier pubertal onset is associated with greater estrogen exposure and increased exposure to estrogen is linked to a higher incidence of adult reproductive cancers (i.e., breast and uterine). Similary, bone density is affected by the interrelationships among endocrine changes, diet, and exercise during adolescence, and the absence of bone accretion increases the likelihood of osteopenia in adulthood. Finally, important immune functions develop during adolescence that may predispose women to infections and autoimmune diseases.

FUTURE RECOMMENDATIONS

The Journal of Adolescent Health recently published a series of papers outlining several priorities for future research on adolescent health and fostering healthy adolescent development. The work group on physical health made several recommendations for future research on pubertal processes, including but not limited to: (a) understanding the neurobiological mechanisms that regulate the onset of puberty; (b) identifying the complex factors that influence the pubertal endocrine process (e.g., diet, stress); (c) clarifying the role of estrogen in controlling bone growth, maturation, and mineral accretion; (d) differentiating the relative influences of nutritional excess, fat metabolism, and genetic risk factors on later cardiovascular risk; (e) examining how sleep during adolescence affects self-control, emotion regulation, and school performance; and (f) investigating how nutrition, adolescent obesity, calcium, and bone accretion have long-term effects on osteoperosis and cardiovascular risk.

A second set of recommendations may be directed at adolescent health care providers. These providers can help girls adjust to pubertal changes in positive ways by providing accurate information, encouraging open communication and questions, and facilitating effective coping in response to alterations in mood, behavior, and biology. Adolescent health care providers have a unique opportunity to educate adolescents and families about the normal developmental processes associated with puberty and to help them identify and solve problems that occur.

SEE ALSO: Birth control, Body image, Menarche

Suggested Reading

  • Archibald, A. B., Graber, J. A., & Brooks-Gunn, J. (in press). Pubertal processes and physiological growth in adolescence. In G. R. Adams & M. Berzonsky (Eds.), Handbook of adolescence. Malden, MA: Blackwell Publishers.
  • Brooks-Gunn, J. & Reiter, E. O. (1990). The role of pubertal processes. In S. S. Feldman & G. R. Elliott (Eds.), The Developing Adolescent. Cambridge: Harvard University Press.
  • Paikoff, R. L., & Brooks-Gunn, J. (1991). Do parent-child relationships change during puberty? Psychological Bulletin, 110, 47—66.

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