Delayed Puberty

What is Delayed Puberty?
The absence of any signs of puberty by age 13 in girls and age 14 in boys is defined as Delayed Puberty. Puberty happens when the pituitary starts making more of two hormones, luteinizing hormone (called LH) and follicle-stimulating hormone (called FSH), which cause the ovaries to enlarge in girls and start producing the female hormone, estrogen and testicles in boys to grow and produce the male hormone testosterone.
In girls, the sequence of events is breast bud appearance, enlargement of breast tissue, development of pubic and axillary hair, further enlargement of breasts, and then menarche or first period. The growth spurt in girls starts shortly after the breasts begin to develop. The whole process occurs over 2-3 years so a girl usually gets her first period roughly about 2-3 years after the appearance of the breast. A girl who has not started to have breast development by the age of 13 is considered to have Delayed Puberty. Boys can start puberty at a wide range of ages, with 95% starting between the ages of 9 and 14, so we consider puberty delayed in boys when it has not started by age 14. The earliest sign of puberty in boys is an enlargement of the testicles (which often goes unnoticed), followed by the growth of the penis and pubic hair. The growth spurt usually starts a year or so after the genitals start to enlarge.

What are the signs and symptoms of delayed puberty in boys?
The key finding is that the penis and testicles do not enlarge by age 14, which is easily noted on physical exams. Often, the testicles have just
started to grow but the penis is still small, which suggests that other signs of puberty will appear in the next 6-12 months. Most boys with
constitutional delayed puberty are short compared with their peers, but because they have a delayed growth spurt, they usually catch up to other
boys by the time they are 18 and have heights in the normal range as adults. 

How is delayed puberty diagnosed?
Sometimes just the physical exam is enough, but many doctors will order some tests to confirm what they suspect and to make sure that the problem is not in the testicles. The most common tests to order are testosterone, LH, and FSH first thing in the morning, when the levels in early puberty are usually higher. Adult testosterone levels vary from 250- 800 ng/dL, and most boys with delayed puberty have testosterone levels of less than 40. An x-ray of the hand and wrist to determine the bone age is often ordered to help predict adult height and is typically at least 2 years behind the chronological age, which means that there is more time remaining for growth. 

How is delayed puberty treated in boys?
For constitutional delayed puberty, the problem will resolve by waiting and reassurance. However, late-maturing boys are often impatient to start growing and do not want to wait another 6-18 months for the pubertal growth spurt to start naturally. Therefore, many pediatric endocrinologists may offer a brief course of testosterone to “jump-start” puberty. It is most often given in the form of a monthly injection for 3 to 6 months. When the boy is seen back after the injections, there is usually a very good gain in height and weight as well as the growth of the penis and pubic hair, and puberty will, in most cases, progress without any further treatment. When the problem is either IGD or damage to the testicles, testosterone is still the treatment of choice, but the dose will need to be increased over time and it will need to be continued well into the adult years. 

What causes puberty in girls to be delayed?
Some girls with delayed puberty are simply late maturers, but once they start, puberty will progress normally. This is called constitutional delayed puberty and is more common in boys than girls. Often, this is something that is inherited from the parents, so it is more likely to occur if the mother started her periods after age 14 (the average is about 12 1⁄2) or if the father was a late maturer. Decreased body fat is a major cause of pubertal delay in girls. It can be seen in girls who are very athletic, particularly gymnasts, ballet dancers, and competitive swimmers. It can also be seen in girls with anorexia nervosa, who engage in extreme dieting or binging and purging because they fear becoming too fat even when they are abnormally thin. Finally, it can be seen in a number of chronic illnesses in which body fat is often decreased. Some girls with delayed puberty may have problems with their ovaries. The ovaries are either not developing properly or are being damaged. This is referred to as primary ovarian insufficiency. The major cause present at birth is Turner syndrome, in which all or part of one of the two X chromosomes is missing. Most girls with Turner syndrome are also extremely short for their age and may have certain distinctive physical features, such as webbing of the neck, a high-arched palate, or arms that bend outward when extended. However, in most cases, Turner syndrome is diagnosed well before age 13 because of short stature. The major acquired cause of ovarian insufficiency is damage to the ovaries as a result of radiation, usually to treat leukemia or certain other kinds of cancer. Occasionally, girls may have their ovaries damaged by the body’s immune system.

How is delayed puberty in girls diagnosed?
The endocrinologist will order blood tests to measure levels of LH, FSH, estradiol, and, in some cases, other tests. Very high levels of LH and FSH will indicate that the ovaries are not working properly, and the pituitary is trying to stimulate them to work harder. If the cause of the
ovarian insufficiency is not clear, a chromosome study or karyotype will be done to see if all or some cells are missing all or part of an X chro-
mosome. If the LH, FSH, and estradiol are all low, the problem could be either decreased body fat (if one of the risk factors listed above is present) or a permanent deficiency of LH and FSH. Other tests may be ordered if a deficiency of multiple pituitary hormones is suspected, and on occasions, a brain MRI may be helpful. A hand x-ray for a bone age is often done, which is typically delayed by 2 or more years, which means that there is still additional time to grow.