Very early or late start of puberty, usually due to a hormonal imbalance
Puberty is the period during which sexual development occurs (see Puberty). In girls, puberty is characterized by a growth spurt, hair growth in the armpits and pubic region, the development of the breasts and reproductive organs, and the onset of menstruation. Although there is some variation in the age of onset of puberty, girls tend to start this process between the ages of 10 and 14. Puberty may be considered abnormal if it starts either earlier than normal (precocious) or later (delayed). Early puberty is occurring if a girl develops breasts before the age of 8 or if menstruation starts before the age of 10. In extreme cases, puberty may begin at the age of 4. Puberty is delayed if menstruation has not started by the age of 16 (see Amenorrhoea) or breast development is absent at the age of 14.
Early puberty is rare and may be due to a hormone disorder. Delayed puberty is more common. Although there may be an underlying cause of delayed puberty, many girls who have not menstruated by the age of 16 are simply late developers, a tendency that often runs in families.
Abnormal puberty can be disturbing for a girl and her family because physical and sexual development will not coincide with that of her peers. Medical advice should be sought as soon as abnormal puberty is suspected.
Puberty in girls is controlled by female sex hormones produced by the ovaries. The production of these hormones is controlled by hormones from the pituitary gland in the brain and from the hypothalamus (the part of the brain that regulates the pituitary gland). Disorders of any of these organs may lead to an abnormally early or late puberty.
Early puberty may be due to a disorder that causes a premature rise in sex hormones. For example, an ovarian cyst developing in childhood may produce sex hormones, causing early sexual development. A tumour of the hypothalamus or damage to the pituitary gland as the result of head injury or an infection such as meningitis may also cause early puberty.
Delayed puberty may be caused by certain chromosome disorders, such as Turner’s syndrome, or less commonly by a pituitary tumour. Excessive weight loss or exercise may create a temporary hormonal imbalance that can lead to delayed puberty.
In many cases of abnormal puberty, no underlying cause is found.
The doctor will carry out an examination to determine whether puberty has started or how far it has progressed. A blood sample may be taken to measure hormone levels or check for a chromosomal abnormality. The doctor may also arrange for MRI or CT scanning of the brain to look for a pituitary tumour, or ultrasound scanning of the ovaries to check for cysts.
If there is an underlying condition, it will be treated. For example, an ovarian cyst may be surgically removed. Hormonal treatment may be prescribed to suspend precocious puberty or to promote sexual development if puberty is delayed. In some cases, delayed puberty is associated with infertility (see Female infertility), and further evaluation and treatment may be required in the future if a woman who has had a delayed puberty wants to have children.
Sometimes, puberty is simply late, and treatment is not necessary. Gaining weight and reducing strenuous activity may help if delayed puberty has been caused by weight loss or exercise.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.