The most common cause of delayed puberty is constitutional delay of growth and puberty, which is sometimes referred to as CDGP.
The first sign of puberty in girls is breast development; this occurs as a result of the ovaries becoming active and producing oestrogens. In boys, one of the earliest signs of puberty is growth of the testes, caused by increasing production of follicle stimulating hormone from the pituitary gland. Delayed puberty is diagnosed when there is no breast development in girls by the age of 13 or growth of testes in boys by the age of 14.
In over 90% of cases, delayed puberty is due to what is known as a constitutional delay in growth and puberty. This means it occurs in children who are healthy but simply have a slower rate of physical development than average. Typically these children will be shorter than other children of the same age. They are often thin and have a family history of delayed puberty. Sometimes delayed puberty and growth can be secondary to a chronic illness, malnutrition, excessive physical exercise and even stress. For example, diabetes, cystic fibrosis and coeliac disease can delay pubertal development while excessive exercise and anorexia, where the proportion of body fat is very low, can also delay puberty.
Puberty is initiated by increasing the production of luteinising hormone and follicle stimulating hormone (gonadotrophins) from the pituitary gland, which is driven by increasing release of gonadotrophin-releasing hormone from the hypothalamus triggered by kisspeptin. When something goes wrong with this control, then hypogonadotrophic delayed puberty occurs; hypogonadotrophic meaning low levels of gonadotrophins. Some forms of gonadotrophin deficiency are caused by genetic defects, for example, Kallman’s syndrome, or alternatively the deficiency can be acquired as a result of a tumour, trauma, surgery or radiation therapy of the head.
Disorders of the testes or ovaries can cause hypergonadotrophic delayed puberty. In this case, levels of gonadotrophins are high, but the ability of the testes or ovaries to detect this is impaired and therefore they cannot respond to the gonadotrophins by producing testosterone and oestrogens, respectively. Chromosomal disorders such as Klinefelter’s syndrome in boys and Turner syndrome in girls result in abnormal development of the testes and ovaries with reduced or absent production of testosterone or oestrogen. Other gonadal disorders include failure of the testes to descend (cryptorchidism), testicular torsion, irradiation of the pelvic/abdominal area, gonadal surgery and mumps (although mumps rarely causes pre-pubertal damage to the testes).
The defining signs of delayed puberty are no breast development in girls by 13 years and small testes of less than 4 ml in volume in boys by 14 years. Another sign can be slow increase in height, although that does not necessarily indicate delayed puberty.
Delayed puberty is roughly estimated to occur in about 3% of children, with 90% of these cases being caused by a constitutional delay. Constitutional delay is 10 times more common in boys than girls.
Constitutional delayed growth and puberty tend to cluster in families although it is not inherited in a simple way. Some very rare causes of delayed puberty are caused by a mutation, which could be inherited from parents, but most cases arise spontaneously in the affected individual.
Diagnosing delayed puberty is relatively straightforward because a physical examination will reveal whether puberty is occurring or not. ‘Pubertal staging’ is key to diagnosis: There are five stages of puberty defined by the degree of breast development, pubic and underarm hair growth, and the size of the testes and length of the penis. These are referred to as the Tanner stages, with number 1 being pre-pubertal with no breast development or testes less than 4 ml volume (the size of the testes can be measured using an orchidometer).
The exact cause of the delayed puberty is more difficult to diagnose. Is it constitutional and will it resolve in time without treatment or is there an underlying cause? A thorough medical history is essential to find out any details of chronic illness, surgery, radiation, mumps, testicular torsion and other factors that may result in delayed puberty.
There are certain investigations that can be undertaken in an outpatient clinic; these will vary between patients depending on their individual symptoms. These include an assessment of bone age by taking an X-ray of the wrists and comparing the images against an atlas of normal bone maturation. Bone age may be delayed in constitutional delayed growth and puberty.
Blood tests may be taken to measure levels of luteinising hormone and follicle stimulating hormone, oestradiol or testosterone and other hormones. This may help to decide whether the delayed puberty is due to loss of gonadotrophins or a primary failure of the testes or ovaries. If Turner syndrome or Klinefelter’s syndrome is suspected then an analysis of the chromosomes will confirm the diagnosis. Scans can also help with diagnosis. This may involve an ultrasound of the pelvis in girls and magnetic resonance imaging (MRI) or computerised tomography (CT) scans of the pituitary and surrounding structures if a tumour or damage to that area is suspected.
Many more boys will seek medical attention for delayed puberty than girls and this is usually because they are concerned about the fact that they are shorter than their peers. Normally, patients with a constitutional delay will progress through puberty, although a little later, and achieve a normal final height. Treatment is usually to just watch and wait with regular checks on height, weight and Tanner pubertal staging measurements, as well as measuring levels of relevant hormones. However, if there are significant psychosocial concerns, a short course of an anabolic steroid may increase growth, and puberty can be induced by giving testosterone to boys or a short course of oestrogen to girls. If pubertal delay is due to chronic disease then treatment is focused on that.
Hormonal treatment is usually reserved for true cases of gonadotrophin deficiency (hypogonadotrophic hypogonadism) and failure of the testes or ovaries such as in Klinefelter’s syndrome, Turner syndrome or any permanent damage to the testes or ovaries. In these cases, increasing doses of testosterone or oestrogen are given to induce puberty; if there is still a deficiency of sex hormones once puberty is completed then life-long sex steroid therapy is required.
Side-effects of steroids are usually mild or they cause no side-effects at all. Testosterone may cause acne or a change in libido, whereas oestrogen and progesterone may cause mild symptoms that are experienced during a normal menstrual cycle such as breast tenderness, mood changes and feeling bloated.
Constitutional delayed growth and puberty does not normally cause any long-term consequences but other causes such as gonadal failure can cause reduced fertility or complete infertility. In such cases, alternative options such as assisted reproductive therapy (ART) are available to help couples to have children. If patients have any concerns, they should discuss them with their doctor or specialist.
Last reviewed: Jul 2021