Puberty is a complex and dynamic process that marks the transition from childhood to adulthood, encompassing various physiological changes driven by hormonal signals. The onset and progression of puberty are influenced by a myriad of factors, including genetics, nutrition, environmental influences, and overall health. Conversely, delayed puberty, when the signs of sexual maturation are absent beyond the typical age range, may arise from a variety of reasons. Understanding both the onset and potential delays in puberty requires a comprehensive exploration of the hormonal, genetic, and environmental factors at play. *Onset of Puberty:* Puberty typically begins with the activation of the hypothalamic-pituitary-gonadal (HPG) axis, a complex hormonal system involving the hypothalamus, pituitary gland, and gonads (testes in males, ovaries in females). The hypothalamus releases gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In turn, these hormones initiate the development of secondary sexual characteristics. One of the earliest signs of puberty is the growth spurt, fueled by increased secretion of growth hormone and enhanced sensitivity to insulin-like growth factor 1 (IGF-1). In boys, the enlargement of the testes and the development of pubic hair typically precede other changes. Girls usually experience breast development, followed by the onset of menstruation. Genetic factors play a significant role in determining the timing of puberty. Family history and ethnic background can influence when an individual enters puberty. Environmental factors, such as nutrition and overall health, also contribute. Adequate nutrition is crucial for the release of hormones involved in puberty, and conditions like malnutrition can delay the onset. *Delayed Puberty:* Delayed puberty is defined as the absence of secondary sexual characteristics by the age of 14 in boys and the age of 13 in girls. Several factors can contribute to delayed puberty, and a thorough medical evaluation is often necessary to identify the underlying cause. 1. *Constitutional Delay:* Some individuals may experience a delay in puberty that is within the normal range, often referred to as constitutional delay of growth and puberty. This is more common in families with a history of later maturation. 2. *Chronic Illness or Malnutrition:* Chronic illnesses, such as inflammatory bowel disease, and conditions affecting overall health can delay puberty. Inadequate nutrition, including eating disorders, may also play a role. 3. *Hormonal Disorders:* Conditions affecting the HPG axis, such as hypogonadotropic hypogonadism or hypergonadotropic hypogonadism, can lead to delayed puberty. Hypothyroidism, a disorder affecting the thyroid gland, can also be a contributing factor. 4. *Genetic Factors:* Genetic disorders or abnormalities, such as Klinefelter syndrome in males or Turner syndrome in fema

1. Presented by,
Dharti B. Bandarwar
M.Sc. Sem-III [Zoology]
Guided by:- Dr. Patil
IOS Nagpur
Onset and Delay
puberty

2. Contents
• Introduction
• Puberty, Influencing factor
• Onset of puberty
• Mechanism
• Stages of puberty [Tanner’s stagging]
• Physiological Changes
• Hormonal Changes
• Diagnosis
• Treatment
• Causes (Abnormal puberty)
• Delay puberty
• Types
• Causes
• Treatment

3. Introduction
• Puberty, In girl is the period which links childhood to the adulthood
• It is the period of gradual development of secondary sexual character
• Common order is:
o beginning of growth spurt
o breast budding (thelarche)
o pubic and axillary hair
o peak growth in height
o menstruation (menarche)
• All this changes are completed by 10-15years.

4. Influencing factor
• The main factor is Genetics
• Body weight
• Nutritional and General health
• Socioeconomical factor
• light
• Geography
• Environmental hormonal disruptors
• Obesity
• Living standard rural and urban area

5. Onset of puberty
• The onset of puberty, the times in life when a person becomes sexually
mature, typically occurs between ages,
Girl : 10-14 years old
Boys : 12-16 years old
• Where body develops and mature
• Puberty prepares body so one day, will be able to have baby
• The changes are caused by natural substances in body called hormones.

6. Mechanism
In prepubertal stage
Cerebral cortex
Hypothalamus
Anterior pituitary
Gonads
Ovary in
female
Testis in
male
Target organ
Adrenal
gland
Release of GnRH
Release of gonadotropins
FSH and LH
Testosterone Estrogen
Sex steroid
Negative
feedback
In pubertal
stage
Visual stimuli
Olfactory stimuli
Body weight
(+ve feedback)
Neural
pathway
Humoral
pathway

7. Tanner’s staging
Stages of
puberty
Female Male
CHARACTERISTCS CHARACTERISTTICS
Stage 1 Adrenarche:maturation of cortex
of adrenal glands, increase
androgen secretion
Maturation of adrenal gland, androgen
secretion increase
Stage 2 Thelarche: Appearance of breast buds
Estrogen secretion increase
Genital development begins
Testosteronesecretion increases
Stage 3 Pubarche: Axillary and pubic hair
appears enlargement of breast
Axillary and pubic hair appears
Enlargement of penis
Stage 4 Gonadarche: gonadal changes,
ovaries begins to grow and
sex hormone production increases
Testes begins to grow,
Further growth of testis,
penis and genitalia
Stage 5 Adult genitalia
Secondary sex characters
Adult genitalia
Secondary sex characters

8. Physiological Changes
female male
A] Structural Changes
• Body Configuration Narrow shoulder,
Broad hips.
Thighs converge
Arms diverge
Shouldersare broader
than pelvis
• Skin Smooth and light Thick, dark and oily.
• Hair growth
Body hair
Face
scalp
Pubic
Fine and scanty
----------
Frontal hair line rounded
Concave
Rough and dark
Moustachesand Beard
Indented at the sides
convex
• muscularity soft Bulky
• Subcutaneousfat Characteristiccorves and
contourto the body
--------------
• Genitalia Adult type Adult type

9. Physiological Changes
Female Male
B] Functionalchanges
C] Behavioral changes Emotional,shy, introvert and
gets attracted toward males
Aggressive, Extrovert and
interest in oppositesex
• Voice No Change Loud, Low pitched, deepensand
breaks.
• BMR Lower 10-15%higher than female
• RBC and Hb Conc. Lower Higher
• Menstrual cycle Menarche Begins Absent

10. Hormonal changes
• Growth hormone secretion increase along with increased gonadotrophins
secretion at the onset of puberty.
• Girls have higher basal levels of GH throughout puberty, reaching
maximal levels around the time of menarche and decreasing thereafter.
• Growth hormone secretion is highly pulsatile, with most pulses occurring
during sleep and with sex steroids increasing pulse amplitude rather than
altering pulse frequency.
• The increase in growth hormone induces peripheral insulin resistance
resulting in compensatory hyper insulin
• This causes a decrease in the different binding proteins
• A reduction of insulin growth factor binding protein leads to an increase
in insulin growth thereby stimulates somatic growth

11. 60
50
40
30
20
10
0
0 10 20 30 40 50 60 70 80 (Age )
Total
Urinary
gonadotrophins
(rat
units/24hr)
puberty
Menopause
female
Male

12. Diagnosis
• True precocious- familial history
• Tanner stage
• No cause could be detected
• X-ray wrist for bone age
• Pelvic sonography to exclude ovarian pathology
• CT brain and MRI brain
• Serum FSH and LH

13. Treatment
• Goals- reduce gonadotrophin secretion decrease growth rate to normal
and slowing skeletal maturation
• DRUGS-
• GnRH agonist
• Medroxy progesterone acetate
• Cyproterone acetate
• Danazol

14. Summery of Pubertal Event
Thelarche Adrenarche Menarche
• 9.8-10.5 years
• Skeletal
growth occurs
simultaneousl
y
• 10.5-11 years
• 12.8 years
• Mean interval
between
thelarcheand
menarche is
approximately
2.5 years

15. Causes (Abnormal puberty)
• Precocious puberty: Appearance of secondary sexual characteristics
before age 8 or menarche before age 9
• Delayed puberty: sexual characteristics don’t develop by the age of 14
or no menstruation until age 16.

16. Delay puberty
• Puberty is said to be delayed when the breast tissue and or pubic hair have
not appeared by 13- 14years or menarche appears as late as 16 years
• The most common cause of delay puberty is a functional delay in the
production of (GnRH) from the hypothalamic neuronal networks that
synergize to initiate the episodic or pulsatile of the GnRH

17. Types
• Physiological Delay
Constitutional delay is the common type
• Pathological Delay
Hypogonadotropic hypogonadism
Hypergonadotropic hypogonadism

18. Causes
• Hypergonadotropic hypogonadism
Gonadal agenesis, 45XO
pure gonadal dysgenesis, 46XX, 46XY
ovarian failure, 46XX
• Hypogonadotropic hypogonadism
constitutional delay
chronic illness
primary hypothyroidism
Kallmann syndrome
• Eugonadism
Anatomical- Mullerian agenesis
imperforate hymen
androgen insensitivity syndrome

19. Treatment
• Hypogonadism-
Cyclic estrogen
Unopposed estrogen 0.3mg/day for first 6 month
The combined estrogen and progestin, sequential regimen is started
• Hypogonadism-
Chromosomal study

20. References
• Guyton and hall Textbook of medical physiology
• GK pal Comprehensive textbook of physiology. Volume 1
• Mammalogy Encyclopedia- sixth Edition
• Modern human physiology, Cornett & Gratz