Early or delayed puberty

Puberty is when a child's body begins to develop and change as they become an adult.

There's usually no need to worry if puberty does not start around the average age. But in some cases, early or delayed puberty could be a sign of an underlying condition that may need treatment.

Signs of puberty

Signs of puberty in girls include:

• developing breasts
• starting their periods

The average age for girls to start puberty is 11. But it's normal to begin at any point between age 8 and 13.

Signs of puberty in boys include developing a:

• larger penis and testicles
• deeper voice
• more muscular appearance

The average age for boys to start puberty is 12. But it's normal to begin at any point between age 9 and 14.

Early puberty

Early puberty is also called precocious puberty.

It is when:

• girls have signs of puberty before age 8
• boys have signs of puberty before age 9

Some children may develop some signs of puberty at a young age, but not other signs.

For example, girls may start periods before the age of 8, but have no breast development.

Talk to your GP if this happens to your child.

Causes of early puberty

It's not always clear what causes early puberty. It may be something that runs in your family.

Sometimes the cause can be:

• a problem with your child's organs, such as their ovaries or thyroid gland
• damage to your child's brain as a result of an infection, surgery or radiotherapy
• a genetic disorder, such as McCune-Albright syndrome
• a problem in your child's brain, such as a tumour

Early puberty mostly affects girls and often has no obvious cause.

Tests for early puberty

Your GP may refer your child to a specialist if they think there might be an underlying cause.

They may need tests, such as:

• a blood test to check their hormone levels
• a hand x-ray to predict their adult height
• an ultrasound scan or MRI scan to check for problems such as tumours

Treatments for early puberty

Treatment for early puberty includes:

• treating any underlying cause
• using medicines to reduce hormone levels and pause puberty

Your specialist usually only recommends treatment with medicines if early puberty in your child could lead to emotional or physical problems.

For example:

• being very short
• having early periods in girls

These may cause a lot of distress for your child.

Delayed puberty

Delayed puberty is when:

• boys have no signs of testicular development by age 14
• girls have not started to develop breasts by age 13
• girls have developed breasts but their periods have not started by age 15

Causes of delayed puberty

It's not always clear what causes delayed puberty. It may be something that runs in your family.

Sometimes the cause can be:

• a long-term illness, such as cystic fibrosis, kidney disease or diabetes
• malnutrition, from a condition such as coeliac disease or an eating disorder
• a problem with your child's ovaries, testes, thyroid gland or pituitary gland
• differences in sex development, such as androgen insensitivity syndrome
• a genetic condition, such as Kallmann syndrome and Klinefelter syndrome

Delayed puberty is more common in boys.

Tests for delayed puberty

Your GP may refer your child to a specialist if they think there is an underlying cause.

Your child may need tests, such as:

• a blood test to check their hormone levels
• a hand x-ray to predict their adult height
• an ultrasound scan or MRI scan to check for problems with their glands or organs

Treatments for delayed puberty

Treatment for delayed puberty includes:

• treating any underlying cause
• using medicines to trigger the start of puberty - doctors usually only recommend medicines if your child is having problems or feeling distressed