1. An Overview of Puberty Betsy Pfeffer MD
Assistant Clinical Professor Pediatrics
Morgan Stanley Children’s Hospital of New York Presbyterian
Columbia University

2. Overview of Adolescent Pubertal Development
From a biologic perspective, the beginning of adolescence is marked by the onset of puberty
Cultural influences on puberty include nutrition, the quality of health care and living conditions

3. Overview of Adolescent Pubertal Development
In the developed world the biologic age of menarche has declined over the past centuries from 16.6 years in 1840 to 12.5 years by 1980
Data on boys, though less reliable, suggest that they may be beginning maturation earlier as well
16.6 yrs in 1840
14.6 yrs in 1920
13.1 yrs in 1950
12.5 yrs in 1980

4. IGF-I and -II are both growth-promoting hormones
Puberty
The exact trigger is unknown, but three distinct changes occur:
Onset of nocturnal sleep-related augmentation of pulsatile LH release (secondary to increased pulsatile GnRH release)
The Gonadotropins
Decrease in sensitivity of the hypothalamus and pituitary to estrogen and testosterone (increased sensitivity to the gonadotropins LH and FSH secondary to maturation of the CNS) LH
FSH
Increases steadily through puberty
Rise during puberty in males and females
Plateaus at Sexual Maturity Rating (SMR) 3 (discussed later)
Males
LH stimulates testicular Leydig cells to produce testosterone
FSH stimulates gametogenesis
Females
FSH stimulates development of primary ovarian follicles and activation of enzymes in ovarian granulosa cells to increase estrogen production
LH stimulates ovarian theca cells to produce androgens and the corpus luteum to synthesize progesterone; midcycle surge of LH induces ovulation
Estradiol
Testosterone
Increases the rate of epiphyseal fusion
Accelerates linear growth
Increases rate of epiphyseal fusion
Increases larynx size, deepening the voice
Stimulates growth of pubic, facial, and axillary hair
Stimulates development of the penis, scrotum, prostate, and the seminal vesicles
Increases libido
Stimulates sebaceous gland secretion of oil
Increases red blood cell mass
Increases muscle mass
Low level enhances linear growth
Stimulates breast development
Stimulates development of labia, vagina, uterus, and ducts of the breasts
Triggers midcycle surge of LH
High level increases the rate of epiphyseal fusion
Increases fat mass of the body
Stimulates development of a proliferative endometrium in the uterus
Progesterone
Stimulates growth of pubic and axillary hair
Converts a proliferative uterine endometrium to a secretory endometrium
The increased secretion of sex steroids from the adrenal gland in the prepubertal and pubertal periods is independent of H-P-A changes
Stimulates lobuloalveolar breast development
These androgens contribute to circulating estrone and testosterone by extraglandular conversion
The major androgens secreted by the adrenal gland are DHA, DHEA-S and androstenedione
Adrenal androgens are not necessary for pubertal development or the adolescent growth spurt (still see puberty in children with adrenal insufficiency)
In both males and females, adrenal androgens
DHA and DHEA-S increase progressively from age 7 to 15
Stimulate linear growth
Stimulate pubic hair growth
Thyroid hormone
Does not change significantly in normal puberty
Glucagon
Permissive action of maximal linear growth--stimulant to skeletal maturation
Insulin
Does not change significantly
Growth Hormone and Somatomedins (Insulin-like growth factors I and II--IGF-I and IGF-II)
Decreased sensisitivity to insulin in adolescents
Secretion increases 30% during puberty
IGF-I and -II are both growth-promoting hormones
Growth Hormone and Somatomedins
They are also stimulated by insulin, prolactin, thyroid hormone and inhibited by glucocorticoids, malnutrition and chronic renal failure
IGF-I and -II are under human growth hormone stimulation (hGH)
hGH and IGF-I rise during puberty
The increase in hGH and IGF-I is most marked during mid and late puberty and correlates best with pubertal stage, bone age and time from peak height velocity
Exact trigger is unknown – in hypothalamic pituitary axis:
Summary of hormone changes:
Augmentation of pulsatile LH secretion during sleep
Decreased sensitivity of hypothalamus to estrogen and testosterone, leading to increased levels of LH and FSH
In males: LH stimulates Leydig cells in testes to produce testosterone and FSH stimulates Sertoli cells in testes to produce sperm later in puberty.
In females: LH stimulates thecal cells in the ovary to produce androgens and FSH stimulates follicular cells in ovary; granulosa cells produce aromatose, which converts ovarian androgens to estrogens.
In females, positive feedback cycle develops – increased estrogen causes burst of GnRH, which causes LH surge
The adrenal gland produces androgens such as DHA, DHEAS, and androstenedione, causing adrenarche
Insulin secretion increases 30% during puberty.
Growth hormone and IGF-1 (somatomedin C) levels rise during puberty,

5. Sexual Maturity Ratings
Tanner developed a scale in 1962 that divides the SMRs into 5 classes based on pubic hair and breasts in females and pubic hair and genitalia in males

6. Tanner Stages Females Breast Stage 1 (B1): Pre-pubertal B2: B3: B4:
SMR 1: pre-pubertal, no hair
SMR 2: light, downy hair along the base of the scrotum and phallus in the male or the labia majora in females
SMR 3: moderate amount of more curly, pigmented, and coarser hair, extending more laterally
SMR 4: hair that resembles adult hair in coarseness and curliness but does not extend to medial surface of thighs
SMR 5: adult type and quantity, extending to medial surface of thighs
Breast Stage 1 (B1): Pre-pubertal
B2:
Breast buds, small amount of glandular tissue
Areola widens
B3:
Breasts enlarge
Areola and papilla: areola continues to enlarge but remains in contour w/ breast
B4:
Breasts continue to larger with more elevation
Areola and papilla form a mound projecting from the breast contour
“ice cream cone”
B5:
Areola and breast in same plane, with papilla projecting above areola
Breast budding is the first physical sign of puberty in the majority of females
Female sexual development usually begins between years

7. Puberty begins at on average at age 10 for whites and 9
Puberty begins at on average at age 10 for whites and 9.25 for African Americans and can take 1.5 to 8 years to complete
Puberty takes an average of 4 years to complete
Earliest onset of sexual development for African-American girls and latest onset for girls from high altitude populations in Asia
Puberty begins with breast budding
PHV occurs about 1 year after breast budding
Average age of menarche is 12 years occurring at SMR 3 or 4 Normal range of menarche Occurs 3.3 years after the start of the growth spurt, 1.1 years after PHV and 2 years after breast budding
Growth slows after menarche.
Menarche: African American 12.1sz
White 12.6

8. Hormonal Control of the Menstrual Cycle

9. Tanner Stages Males Genital Stage 1 pre-pubertal Genital Stage 2 (G2)
Testicular volume 1.6-6ml,
scrotum red, thinner, larger
phallus unchanged
Testicular volume 6-12 ml
Genital Stage 3 (G3)
scrotum enlarges
phallus increases length
Genital Stage 4 (G4)
Testicular volume ml
Scrotum enlarges and darkens
Phallus increases in length and circumference
Genital Stage 5 (G5)
Testicular volume >20 ml
Scrotum and phallus adult size

10. Puberty begins age years and can take 2-5 years to complete Whites avg 11 African American males avg age Puberty takes an average of 3 years to complete
Puberty begins with testicular enlargement, The bulk of testicular enlargement is attributed to the sperm producing tubules, androgen producing leydig cell mass is small
Earlier onset of sexual development for African-American males
Ejaculation usually occurs during SMR 3, SMR 4 is associated with nocturnal emissions, fertility, but sperm (spermarche) are present in some quantities by SMR 3
Spermarche age 12-14
Peak height velocity occurs later for males than females corresponding to SMR 3-4

11. Puberty The normal range in pubertal development is very broad
Early maturation is a positive experience for boys but may be negative for girls
Late maturation is usually more difficult for boys than for girls
Adolescents compare themselves to their peers and internalize the reaction of others to their changing bodies
Variations in the timing of puberty can have psychosocial impact on the teen who varies from the mean. Early developing males have greater self confidence and greater likely hood of academic, social and athletic success. Early puberty in girls appears to be related to lower self esteem and more concerns about body image. However, unlike boys, late developing girls do not seem to have problems with poor self esteem. Poor self esteem correlates with many of the problems that arise during adolescence including difficulties in relationships, risky behavior and poor school performance.

12. Sleep: A Complete Mystery
Increased need for sleep at puberty
Adequate sleep is essential to support healthy physical development
During puberty changes in melatonin secretion cause a sleep delay leading to later sleep onset and later waking times
Adolescents need hours of sleep/night
Sleep enhances the consolidation of learning
Insufficient sleep
Irritability/Low frustration tolerance
Difficulties with attention and self control
Hazen 2008
Dahl 2009
Cicadian is biologic clock
Dr. Mary Carskadon is a professor of psychiatry and human behavior at Brown University and director of chronobiology and sleep research at E.P. Bradley Hospital in Providence, R.I
Harvard Dr. Robert Strickgold
Dr.Carlyle Smith Trent University

13. Tasks of Adolescence Physical Development/Puberty
Psychosocial Development
Cognitive Development
Biologic and cognitive maturation are universal instigators of psychosocial development in adolescence, their effects are moderated by the social ecology in which they occur

14. Stages of Adolescent Development
In all countries adolescence go through the same stages but age ranges may vary
Early Adolescence: USA years
Middle Adolescence: USA years
Late Adolescence: USA years

15. Physical Changes Early Adolescent
Girls:
Growth and growth spurts begins
Beginning of pubertal changes breasts/genitalia/pubic hair
Weight changes-body shape and size

16. Physical Changes Early Adolescent
Boys:
Development of the testes and scrotum is usually the first sign of puberty in boys
Pubic hair
Voice changes
Gynecomastia common
Testicular enlargement is the first physical sign of puberty in about 98% of males
Gynecomastia occurs SMR 2-4, peaks around age 14, occurs in 50% of males. Can be unilateral or bilateral. Regresses over 2 years

17. Physical Changes Early Adolescent
Boys and Girls:
Wide range of normal
Acne
Girls tend to lose less of their body fat than boys
An awkwardness as various body parts grow at different rates
Biologic changes in the brain causing dynamic emotional and cognitive changes .
Girls begin pubery about 1-2 years earlier than boys
The head, hands, and feet are the first parts of the body to reach their mature size.

18. Physical Changes Mid Adolescence
Girls:
Breast development
Nipples swell , breasts may feel tender and sensitive
Breasts fill out over three to four years. One breast may grow faster than the other
One or both breasts may secret a small amount of milky fluid
Broadening hips leading to rounded feminine figure

19. Physical Changes Mid Adolescence
Boys:
Growth spurt in height usually occurs
Often the arms and legs lengthen before the trunk of the body, can cause awkwardness
Faster muscle growth in boys leads to greater strength
Penis growth
Development of pubic, facial and body hair. Typically facial and body hair appear about two years after pubic hair.

20. Physical Changes Late Adolescence
Females
By 16 years most young women have completed puberty, the growth rate slows, there is pubic and body hair, a rounded and curved figure because of widened pelvis, hips and breasts
With a well established menstrual cycle, a young woman at this point is physically able to produce offspring

21. Physical Changes Late Adolescence
Males
By 16 to 18 years most males have completed puberty, their growth rate begins to slow, their shoulders have broadened, limbs and trunk are muscular and they have adult body and facial hair
Produce sperm and are physically able to produce offspring

22. Psychosocial Changes Early Adolescent
Begin to separate from parents and identify with peers
Confrontational with parents
Preoccupation with self
Preoccupation with being like peers
Conformity
Same gender in clique
Erik Ericson is the most influence theorist of emotional development
He looked at adolescence as a period of identity formation and separation from adult caregivers

23. Psychosocial Changes Early Adolescent
Interest in other gender for friendship
Travel in “packs”
Greater need for privacy
Still need “down-time”
Mood swings/Erratic behavior
Lack of impulse control
Down time is time on their own, time not devoted to a specific activity

24. Psychosocial Changes Mid Adolescence
Peak
Parental conflicts
Peer involvement
Risk taking behavior
Conformity with peer values
Feeling of omnipotence and immortality
Egocentric
Personal fable, belief in own uniqueness and invulnerability
Self centeredness and vanity
Sense of grandiosity and invulnerability coupled with a limited capacity to fully grasp the ramifications of risky behaviors and their long term health risks.

25. Psychosocial Changes Mid Adolescence
Increasing independence
Less idealistic vocational aspirations
Questioning “who is the real me ?”
Behave differently with different people
Conflicting view of the self can be troubling
Ability to recognize that they have different roles with different people but don’t yet understand why and this can be troubling

26. Psychosocial Changes Late Adolescence
Integration of the diverse views of self
Less importance placed on peer group
May accept parental values or develop own
Realistic vocational goals
Less self centered

27. Psychosocial Changes Late Adolescence
Decreased impulsivity and increased ability to compromise
Fully understanding lack of invincibility
Ability to compromise and set limits
Refinement of moral and religious values

28. Cognitive Development
Much of modern thinking about cognitive development in adolescence is gotten from the work of the Swiss biologist/psychologist Jean Piaget ( )
He outlined four main stages of cognitive development from birth to adolescence
The shift from the third stage of concrete thinking to Piaget’s highest stage of cognitive formal operations (the ability to think hypothetically and abstractly) begins around age 11
Sensorimotor
Pre operational represent objects symbolically in the mind 2-7
Concrete operational concerned with what happens 7-11 can’t consider possibilities that are not real
Formal operations >11
Definition of concrete thinking Thinking characterized by a predominance of actual objects and events and the absence of concepts and generalizations
Abstract thinking the final, most complex stage in the development of cognitive thinking, in which thought is characterized by adaptability, flexibility, and the use of concepts and generalizations. Problem solving is accomplished by drawing logical conclusions from a set of observations, such as making hypotheses and testing them

29. Cognitive Changes Early Adolescence
Retain concrete thinking
Begin to question authority and societal standards
Conformist morality of childhood
Learning by trial and error
Beginning abstraction
Imaginary audience, on stage all the time, others are thinking only about them

30. Cognitive Changes Mid Adolescence
Thinking tends to be less childlike, more abstract, introspective and analytic
Begin to realize they are sexual beings
Can consider facts and make better decisions based on knowledge of the consequences of their choices
Sensitive to criticism
Increased openness of feelings and sensitivity to the feelings of others
Continue to be influenced by peers
By mid adolescence teens begin to understand:
the components of healthy and unhealthy relationships and the value of loving long term relationships
the consequences of sexual involvement
including HIV, STI’s, pregnancy
That they can express their sexuality in ways that may or may not include sexual intercourse

31. Cognitive Changes Late Adolescence
Conceptualize/verbalize thoughts
Full adult reasoning/identity
Ability for abstract thinking
Understanding consequences of behavioral choices
Increased thoughts about more global concepts such as justice, history, politics, patriotism and their emerging role in adult society
Adolescents often regress during times of stress.
Issues of emancipation for late adolescents
Living away from home
University
Pre-college work
Military
Competence at independent financial management
Earning a living
Financially self-sufficient
Becoming a teenage parent

32. Brain Development
There may be a biologic basis for the increased risk taking and impulsivity in adolescence
Areas of the brain that are associated with the capacity evaluate risk and reward are one of the last regions of the brain to mature Hazen 2008
Areas of the brain associated with working memory, emotion regulation and the capacity for long term planning mature during adolescence Hazen 2008
In the frontal part of the brain, the part of the brain involved in judgment, organization, planning, strategizing -- those very skills that teens get better and better at -- this process of thickening of the gray matter peaks at about age 11 in girls and age 12 in boys, roughly about the same time as puberty. After that peak, the gray matter thins as the excess connections are eliminated or pruned. This area of the brain (prefrontal cortex) does not reach full maturity until around age 25

33. Hardwiring the Brain
According to Dr. Jay Giedd of the NIMH during adolescence
A second wave of overproduction of gray matter occurs
A process called “pruning” occurs where connections among neurons in the brain that are not used wither away, while those that are used stay—the “use it or lose it” principle
Teens may actually be able to control how their own brains are wired and sculpted
Teens who “exercise” their brains by learning to order their thoughts, understand abstract concepts, and control their impulses are laying the neural foundations that will serve them for the rest of their lives
Overproduction of grey matter was thought to happen only in the first 18 months
It is
thought that this pruning process makes the brain more efficient by strengthening the
connections that are used most often, and eliminating the clutter of those that are not
used at all.
The period of pruning, in which the brain actually loses gray matter, is as important for brain development as is the period of growth. For instance, even though the brain of a teenager between 13 and 18 is maturing, they are losing 1 percent of their gray matter every year. PBS

34. Brain Development
Evidence that some brain changes are linked to puberty while other changes are dependant on age/experience Dahl 2004
Increase in the volume of white matter facilitating connections between cortical regions occurs into the twenties
National Institute of Mental Health 2001
Structural brain imaging occurring over the past decade have revealed more information about the developing brain
the highly active and more primitive emotional limbic region
wrapping white matter (myelin) around other connections to stabilize and strengthen them.

35. Brain Development
Many important decisions are made by teens in affectively charged environments and because of incomplete myelination, executive brain regions don’t modulate decision making and poor decisions are made Hazen 2008
Poor decision making in real life situations despite measurable aspects of decision making approach adult levels of competence by age Dahl 2004

36. Brain Development
When challenges are presented to teens in less emotionally charged settings, they make safer decisions and use higher brain functions more effectively Hazen 2008
True of adults too
Importance of anticipatory guidance
Structural brain imaging have shown that brain development continues through early adult years and that there may be a biologic basis for the increased risk taking in adolescence. Areas of the brain that are associated with the capacity evaluate risk and reward is one of the last regions of the brain to mature. Areas of the brain associated with working memory, emotion regulation and the capacity for long term planning mature during adolescence. (Adolescent Psychosocial Development: A Review)

37. Putting it All Together
Helpful to determine where a teen “is at”
Understanding the developmental phases of adolescence can help us place the adolescent in an appropriate context
Once we understand the developmental tasks of adolescence and we couple this with the acquisition of skills that aid in the communication with an adolescent
Assure Confidentiality
Engage the adolescent as a therapeutic ally
Active listening and observing
Reflective responses
Clarify inferences
Summarizing statements
Then….
Clarifying inference..that seems to be upsetting to you

38. The Goal
We can help successfully guide our youth community into making thoughtful and healthy decisions along their journey into becoming responsible and productive adults

39. Bibliography
Rosen, D. “ Physiologic Growth and Development During Adolescence” Pediatrics in Review 2004
Patton, G. “Pubertal Transitions in Health” The Lancet 2007
Hazen, E. et al“Adolescent Psychological Development: A Review” Pediatrics in Review 2008
Gutgesell, M. “ Issues of Adolescent Psychological Development in the 21st Century” Pediatrics in review 2004
Ginsburg, K. “ Engaging Adolescents and Building on Their Strengths” AAP Adolescent Health Update 2007
Cavanaugh, R. et al “Managing the Transitions of Early Adolescence” AAP Adolescent Health Update 2008
Bight Futures: Guidelines for Health Supervision of Infants, Children and Adolescents AAP
Kreipe, R. “ Introduction to Interviewing: The Art of Communicating with Adolescents” AMSAR 2008
Teenage Brain: A Work in Progress (Fact Sheet) National Institute of Mental Health 2001
Dahl, R. “Beyond Ragging Hormones: The Tinderbox in the Teenage Brain”. Cerebrum: The Dana Forum on Brain Science 2003
Dahl, R. “Adolescent Brain Development: A Period of Vulnerabilities and Opportunities” Annals New York Academy of Science s 2004
Dahl, R. “ The Consequences of Insufficient Sleep for Adolescents” Phi Delta Kappan 1999
Spinks, S. ‘ Adolescents and Sleep” Frontline PBS 2002