Early or late puberty: when should parents worry?

Parents often notice puberty changes before anyone else, and wonder whether their child is “too early” or “too late”. Puberty timing varies a lot between healthy children, and it often runs in families. But there are clear age limits beyond which a check-up is worthwhile, because the cause can affect final height, emotional wellbeing and long-term health.

What is normal puberty?

Puberty is controlled by signals from the brain and pituitary gland to the ovaries or testicles.

• In girls, the first sign is usually breast budding, between about 8 and 13 years. Pubic hair follows, and the first period usually comes about two to three years after breast budding. Girls have their growth spurt early in puberty.
• In boys, the first sign is enlargement of the testicles, between about 9 and 14 years. This is easy to miss. Pubic hair, a growth spurt, voice change and facial hair come later.

What counts as early (precocious) puberty?

Puberty is generally considered early if:

• a girl develops breasts or pubic hair, or has a growth spurt, before 8 years
• a boy has testicular or penile enlargement, pubic hair or a growth spurt before 9 years

A period before the age of 10 also needs review.

What causes early puberty?

• In girls, most cases are central precocious puberty with no serious underlying cause. The brain’s puberty “clock” simply starts early. Excess weight is linked with earlier puberty.
• In boys, early puberty is less common and more often has an underlying cause, so it always needs investigation.
• Less common causes include brain tumours or other brain conditions, past brain injury or radiation, adrenal or ovarian conditions, congenital adrenal hyperplasia, McCune-Albright syndrome, an underactive thyroid, and exposure to hormone creams or oils used by adults in the home.

Not every early change is true puberty. Isolated breast budding in very young girls, or early pubic hair or body odour from the adrenal glands (premature adrenarche), can be milder variants. A specialist can tell these apart.

Why does early puberty matter?

Children with early puberty are often tall for their age at first, but their bones mature early and growth stops sooner, so adult height can end up shorter. Early periods or body changes can also be emotionally hard for a young child. When needed, treatment with medicines that pause puberty is effective and is stopped at a suitable age. Your doctor will discuss whether treatment is needed.

What counts as late (delayed) puberty?

Puberty is generally considered delayed if:

• a girl has no breast development by 13 years, or no period by 15 years or more than three years after breast development began
• a boy has no testicular enlargement by 14 years

Puberty that starts and then stops, or does not progress over a couple of years, also needs review.

What causes late puberty?

• Constitutional delay of growth and puberty, a “late bloomer” pattern, is the most common cause, especially in boys. These children are often shorter than classmates and one parent was often late too. They usually go through normal puberty later.
• Chronic illness or poor nutrition, such as coeliac disease, inflammatory bowel disease, poorly controlled diabetes, kidney disease or eating disorders.
• Heavy exercise with low body weight, especially in girls who are athletes or dancers.
• Hormone conditions, such as an underactive thyroid, high prolactin or growth hormone deficiency.
• Problems with the ovaries or testicles, such as Turner syndrome in girls or Klinefelter syndrome in boys.
• Problems with puberty signals from the brain, sometimes with a poor sense of smell (Kallmann syndrome).

Telling a “late bloomer” apart from a lasting hormone problem can take time and follow-up.

Which tests do doctors use?

A paediatric endocrinologist will examine your child, plot height and weight on growth charts, and may order:

• bone age, an X-ray of the left hand and wrist that shows how mature the bones are
• blood tests such as LH, FSH, oestradiol or testosterone, TSH and prolactin
• a stimulation test to see whether the puberty signals have switched on
• a pelvic ultrasound in girls
• an MRI of the brain in some children, especially boys with early puberty or children with neurological symptoms
• genetic tests such as a karyotype when Turner or Klinefelter syndrome is suspected

Growth is assessed using Indian Academy of Pediatrics growth charts for Indian children. Read is my child too short, and use the BMI calculator for weight.

How is late puberty treated?

Many late bloomers need only reassurance and follow-up. If delay is causing distress, your doctor may discuss a short course of hormone treatment to start puberty. Children with a lasting hormone problem need longer-term hormone replacement, managed by a specialist. Girls with irregular periods once puberty is established can read which hormone tests irregular periods need, and adult men with low testosterone can read low testosterone in men.

What should I ask the doctor?

• Is my child’s puberty truly early or late, or within the normal range?
• What is the likely cause, and which tests are needed?
• How will this affect my child’s final height?
• Does my child need treatment, or can we watch and wait?

If you are worried about your child’s puberty, book a consultation.