Early and delayed puberty – here’s what you need to know.

  • April 12, 2021
  • Paediatric/Adolescent Gynaecology

What is puberty?

Puberty is a fascinating sequence of events leading to huge developmental changes in our daughters.

What causes puberty?

Puberty is actually under the control of our brain (many parents may be already be acutely aware of this!), in an area called the hypothalamus and pituitary. The adrenal glands also play an important part. These glands produce signals that cause the production of estrogen, progesterone, testosterone, growth hormone, and many other chemicals that are essential for development.

In the developing fetus, the pituitary gland and the ovaries are active and produce hormones which trigger sexual changes and development.

After birth, the pituitary gland enters a phase of latency between infancy and the onset of puberty.

Even before any physical signs begin to show, these areas of the brain re-activate and start to produce chemical signals that result in puberty. This is defined as the developmental stage during which secondary sexual characteristics appear (breasts, pubic hair, body odour, pubertal growth, shape changes).

When does puberty start?

There is a huge variation in how adolescents will progress through puberty; however, breast budding with (or shortly followed by) hair development is most common. Periods usually follow this within 12-24 months, and usually after rapid growth spurt seen in puberty has already taken place.

When do the signs usually start appearing?

  • The budding of breasts is the first clinical sign in most young women, occurring at a mean age 10.9 years (95% will range 8.5 to 13.3 years of age).
  • Pubarche (pubic hair) starts at around 11 years (8.5y–13.5y)
  • The pubertal growth spurt happens around 11.25 years (10y–12.5y)
  • Menarche (first menstrual bleeding) takes place at around 12.5 years (10.5y–14.5y)
Timeline of pubertal development

Delayed puberty

Delayed puberty in females is defined as a lack of puberty – the lack of secondary sexual characteristics, such as breasts, hair or periods, by 13 or 14 years of age. It can also be defined as when periods start, but breast development does not follow with 2 to 3 years. Delayed puberty should be reviewed, as it can be a sign of a serious undiagnosed gynaecological or health condition.

Precocious (early) puberty

Puberty can also start too early. Precocious puberty is the onset of puberty at an abnormally early age; usually before the age of 8 in girls. This warrants an urgent referral to an Paediatric Gynaecologist or Endocrinologist.

Even if puberty is not precocious, may girls that start menses when they are immature – only 10, 11 or 12 years of age – will struggle with managing it. This may include associated discomfort, irregular cycles, impact on sports, and managing hygiene whilst at school. Additionally, if menses are heavy, it can be physically harder for younger adolescents to keep up with the demands of the associated iron loss. If menses are impacting on your daughter, she may need some additional help.

When should I seek help?

The onset of menstruation (menses, periods) does not mean that development is complete. The highly complex pathways between the brain and the ovaries are still developing. In particular, the process of ovulation (releasing an egg) is still establishing, and the failure to ovulate with all cycles explains why teenagers often have irregular periods. This can also mean that some teenagers will have heavier or prolonged bleeding. If this is significant, they may need to see an adolescent gynaecologist.

Teenagers are not little adults. They are still developing throughout adolescence – up to the age of 21. For this reason, adolescents benefit from seeing a gynaecologist that specialises in understanding the treatment and medicine options for children, as treatment options differ to adult women.

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