3. Normal and Abnormal Puberty

Normal and Abnormal Puberty

This PatientPlus article is written for healthcare professionals so the language may be more technical than the condition leaflets. You may find the abbreviations list helpful.

See also separate articles Delayed Puberty and Precocious Puberty.

Puberty is the process by which a child's body becomes an adult body, associated with the appearance of both primary and secondary sexual characteristics and capable of reproduction.[1] Growth accelerates in the first half of puberty and stops at the completion of puberty. Puberty usually begins between 8 and 14 years of age in girls and 9 and 14 years of age in boys. Data from the USA indicate that girls are generally maturing at an earlier age than they did 30 years ago.[2]

Although girls are generally considered to mature earlier than boys, the differences in timing are less than generally perceived. Testes require higher levels of gonadotrophin stimulation than ovaries - hence, the later puberty. However, on average, spermarche occurs at about the same time as menarche with attainment of reproductive capability being achieved at about the same age.

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  • The onset of puberty is signalled by the secretion of increasing frequency and amplitude of pulses of gonadotrophin-releasing hormone (GnRH).

    Normal puberty in girls

    • Breast enlargement, occasionally initially unilateral, is the first obvious sign of puberty and occurs on average between 10 and 11 years of age. It is important to examine patients when they are in the supine position to help distinguish true breast enlargement from fat. Breast buds may initially be unilateral. Gradually the breast diameter increases and the areola darkens and becomes more prominent.
    • Pubic and axillary hair growth in girls is a sign of adrenal androgen secretion. It starts at about the time of apocrine gland sweat production and the common complaint of axillary odour. Genital examination may reveal pubic hair and changes in the vaginal mucosa (from red prepubertally to pastel pink, moist mucosa of the oestrogenised vagina). Clitoral enlargement and acne suggest androgen excess and virilisation.
    • Menarche usually occurs about 2-3 years after the start of breast development (thelarche). In one British cohort study the average age at menarche was 12.9 years and the average duration of puberty was 2.7 years.[3]
    • The growth spurt occurs earlier in female puberty. It is usually maximal (about 8 cms/year) during Tanner's breast stages 2 and 3. and reduces to 4 cm/year at menarche.
  • Examination:
    • May reveal pubic hair and changes in the vaginal mucosa (from red prepubertally to pastel pink, moist mucosa of the oestrogenised vagina).
    • Clitoral enlargement and acne suggest androgen excess and virilisation.
    • Vaginal examination should only be performed if the patient is already sexually active.
    • Rectal examination should never be performed (information better from ultrasound).
    • Breast examination: supine position to help distinguish true breast enlargement from fat.
    • Breast buds may initially be unilateral.
    • Gradually the breast diameter increases and the areola darkens and becomes more prominent.
    • Skin: mild acne in early puberty is normal, but rapid onset and progression of acne again suggest androgen excess.

Tanner's stages of puberty in girls are summarised in the table below.[4]

Pubertal Stages in Girls
Tanner stage Breasts Pubic hair Growth Other Other
Stage 1 Prepubertal - elevation of papilla only. Prepubertal villus hair only. Basal level - 5 cm to 6 cm per year. Adrenarche. Ovaries grow and enlarge.
Stage 2 Breast bud appears under an enlarged areola (mean age 11.2 years). Sparse hair along labia (mean age 11.9 years). Accelerated growth - about 7 cm to 8 cm per year. Clitoral enlargement with labial pigmentation. Uterine enlargement.
Stage 3 Breast tissue grows beyond areola but without contour separation (mean age 12.4 years). Hair coarser and pigmented - spreads across pubes (mean age 12.7 years). Peak velocity - about 8 cm per year (mean age 12.5 years). Axillary hair (mean age 13.2 years). Acne (mean age 13.2 years).
Stage 4 Projection of areola - papilla forms a secondary mound (mean age 13.1 years). Adult pattern but without spread to medial thigh (mean age 13.4 years). Deceleration- less than 7 cm per year. Menarche (mean age 13.3 years). Regular periods (mean age 13.9 years).
Stage 5 Adult breast contour with projection of papilla only (mean age 14.5 years). Adult with spread to medial thigh but not up linea alba (mean age 14.6 years). Cessation of growth at around 16 years. Adult genitalia.  

Normal puberty in boys

  • The first signs of puberty often go unnoticed. Testicular enlargement can be detected quite early, but is often subtle enough in the early stages to go unnoticed. It usually occurs between the ages of 12 and 13 years. The prepubertal testis is about 2 ml in volume with puberty taken to begin when a volume of around 4 ml is attained.
  • Testicular growth starts as early as 10 years of age, associated with enlargement of seminiferous tubules, epididymis, seminal vesicles and prostate.
  • Enlargement of testes depends on increased FSH. Prader's orchidometer (a string of different volume 'beads'/testes for comparison by the examiner) should be used to assess testicular size.
  • Progressive signs of androgen excess without an increase in testicular volume should raise concern about precocious pseudopuberty (androgenic effect from another source such as congenital adrenal hyperplasia or testicular tumour).
  • Penile and scrotal enlargement occur typically about a year after testicular enlargement is noticed.
  • Signs of change in penis (growth), scrotum (reddening and thinning) and pubic hair growth follow 1-2 years after testicular enlargement.
  • Pubic hair typically appears at a similar time.
  • Pubic hair growth without other changes (premature adrenarche) suggests adrenal androgen production (congenital adrenal hyperplasia (CAH), Cushing's syndrome, adrenal tumour).
  • Approximately half of boys have some degree of breast hypertrophy.
  • Later signs include growth spurt, voice deepening, acne and facial hair.The growth peak starts 2-3 years earlier in girls. Growth spurts start with the hands and feet and move proximally to finish with the trunk.
  • A greater and later growth spurt occurs in boys than in girls. The growth spurt is on average 2 years later than girls and ceases only 1 year later.

Stages of normal puberty (Tanner's stages) in boys are shown in the table below.[4]

Pubertal Stages in Boys
Tanner stage Genitalia Pubic hair Growth Other
Stage 1 Prepubertal - testes less than 2.5 cm. Villus hair only. Basal rate - 5 cm to 6 cm per year. Adrenarche.
Stage 2 Thinning and reddening of scrotal skin (mean age 11.9 years).
Testes 2.5 cm to 3.2 cm.		 Sparse growth base of penis (mean age 12.3 years). Basal rate as above. Reduction in total body fat.
Stage 3 Growth of penis (mean age 13.2 years).
Testes 3.3 cm to 4 cm.		 Thicker hair - spreads to mons pubis (mean age 13.9 years). Accelerated growth - 7 cm to 8 cm per year. Gynaecomastia (mean age 13.2 years).
Voice break (mean age 13.5 years).
Increase in muscle mass.
Stage 4 Growth of penis and glans with darkening of scrotum (mean age 14.3 years).
Testes 4.1 cm to 4.5 cm.		 Adult but no spread to medial thigh (mean age 14.7 years). Peak velocity about 10 cm per year (mean age 13.8 years). Axillary hair (mean age 14 years).
Voice change (mean age 14.1 years).
Acne (mean age 14.3 years).
Stage 5 Adult genitalia (mean age 15.1 years).
Testes greater than 4.5 cm.		 Adult with spread to medial thigh but not linea alba (mean age 15.3 years). Deceleration and cessation (about 17 years). Facial hair (mean age 14.9 years).
Muscle mass increases further and beyond Stage 5.

There are many causes of abnormal puberty.[1] The main aim of assessment is to determine those children with an underlying pathological abnormality from those with constitutional and benign pubertal changes. It is important to recognise abnormal timing and progression of puberty. This may require a combination of clinical assessment, investigations and expert advice.

History

  • Take a full history of previous growth and development.
  • Record the timing and sequence of physical milestones and behavioural changes of puberty.
  • Record full medical and surgical history.
  • If the individual is underweight and has delayed puberty take a nutritional history.
  • Detail any family history of early or delayed puberty and any genetic disease.

Physical examination

  • Plot growth velocity on a growth chart. Has there been a change compared with old records?
  • The most important systems to examine are neurological and endocrine.
  • Look for evidence of thyroid or other endocrine dysfunction.
  • Optic fundi, visual fields and sense of smell should be checked to look for evidence of a pituitary tumour.
  • The genitalia and body habitus should be examined and the stage of puberty documented.
  • Photographs are useful to document the stage of puberty. However, such clinical photographs need appropriate consent and are best undertaken in hospital medical photography departments.

Investigations should be used selectively and based on a thorough clinical assessment.

  • Assessment of bone age: an X-ray of the left wrist can be used to determine skeletal age compared with chronological age.
  • Blood tests include FSH/LH levels, oestrogen assay, 17-OH progesterone/DHEA assay, testosterone levels, prolactin levels, beta human chorionic gonadotrophin (beta-hCG) and TFTs.
  • Gonadotrophin-releasing hormone (GnRH) stimulation test and other tests of pituitary function (see separate article Pituitary Function Tests).
  • Diagnostic imaging may include:
    • Pelvic ultrasound: essential in gonadotrophin-independent precocious puberty (precocious pseudopuberty) in girls to detect ovarian tumours or cysts.
    • Testicular ultrasound: to detect tumour.
    • Adrenal ultrasound: to detect tumour, but much better imaging with MRI scan.
    • Plain hand and wrist X-rays for bone age.
    • Brain MRI scan - indications include:[5]
      • All males with sexual precocity.
      • Patients with neurological signs or symptoms.
    • Pelvic MRI scan to assess uterine function and ovarian pathology in girls.
    • Chromosomal analysis to detect chromosomal abnormality.
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Further reading & references

  1. Traggiai C, Stanhope R; Disorders of pubertal development. Best Pract Res Clin Obstet Gynaecol. 2003 Feb;17(1):41-56.
  2. Cesario SK, Hughes LA; Precocious puberty: a comprehensive review of literature. J Obstet Gynecol Neonatal Nurs. 2007 May-Jun;36(3):263-74.
  3. Christensen KY, Maisonet M, Rubin C, et al; Progression through puberty in girls enrolled in a contemporary British cohort. J Adolesc Health. 2010 Sep;47(3):282-9. Epub 2010 Apr 21.
  4. Blondell RD, Foster MB, Dave KC; Disorders of puberty. Am Fam Physician. 1999 Jul;60(1):209-18, 223-4.
  5. Chalumeau M, Hadjiathanasiou CG, Ng SM, et al; Selecting girls with precocious puberty for brain imaging: validation of European evidence-based diagnosis rule.; J Pediatr. 2003 Oct;143(4):445-50.
Original Author: Dr Richard Draper Current Version:
Last Checked: 22/06/2011 Document ID: 2681  Version: 23 © EMIS

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

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