Stopping Precocious Puberty With Puberty Blockers

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Precocious puberty is when a child starts to show signs of puberty earlier than is considered to be normal. For boys, signs of puberty before age 9 are usually considered to be precocious. For girls, signs of puberty before age 8 are considered potentially problematic. However, some young girls experience only the puberty symptoms of early breast growth or pubic hair development. Early pubic hair growth is particularly common in young black girls.

These signs alone are not necessarily considered to be precocious puberty.

It is worth noting that evidence suggests that puberty has been occurring at younger and younger ages over time. There are several hypotheses for why this may be occurring. Earlier puberty might be linked to improved nutrition in childhood. It could be associated with the increasing frequency of childhood obesity. On the other hand, there is evidence that it could be associated with changes in the environment. Scientists have pointed to everything from stress to light cycle changes to chemical contaminants as possibly contributing to the trend The truth is, no one really knows.

It is important, however, to recognize the difference between precocious puberty and the tendency for puberty to be earlier in the population as a whole. Precocious puberty is puberty that happens early enough that it could potentially cause social or medical problems for the young person experiencing it.

Are There Problems Associated with Precocious Puberty?

A number of different conditions have been associated with precocious puberty. However, the evidence for some of these conditions is greater than others. There is, for example, strong evidence that children who experience precocious puberty will have an early growth spurt but then end up at a shorter adult height than their peers.

Short stature is mostly a problem for children who start puberty at a very early age. It occurs because their bones mature and stop growing too quickly. This is one condition that can be positively affected by puberty blockers.

Evidence for other problems associated with precocious puberty is more mixed. Some studies suggest that precocious puberty may lead to inappropriate sexual behaviors. Studies have found, inconsistently, that precocious puberty is associated with behavioral problems and poor social skills. There is also some evidence that precocious puberty can lead to emotional problems that last into adulthood. However, some of the social and emotional side effects associated with the stress of early puberty can be reduced by good parental support and education.

There is some evidence that early puberty may be associated with other long term health risks. There may be a slightly increased risk of diabetes, heart disease, or stroke. However, these risks are confounded by the fact that obesity is linked to both early puberty and to all three health conditions. There may also be a slightly higher risk of breast cancer in young women who have their first period at earlier ages.

What Causes Precocious Puberty?

A number of different factors have been associated with precocious puberty, although the precise cause is still a mystery.

Puberty blockers are used to treat what is known as central precocious puberty. Central precocious puberty occurs when the brain starts sending out signals for puberty to begin.

Some factors associated with central precocious puberty include:

  • genetics
  • early nutritional problems followed by obesity
  • brain and central nervous system injuries

Unfortunately, many cases of central precocious puberty are idiopathic. That means that doctors have no idea why they occur.

There is a second category of precocious puberty known as peripheral precocious puberty or GnRH-independent precocious puberty. These cases are caused by abnormal hormone production that starts outside the brain.

What Are Puberty Blockers? How Do They Stop Precocious Puberty?

Puberty blockers are more commonly known as GnRH analogues or GnRH agonists. They are also referred to as GnRHa treatment. These drugs interrupt the signals that the brain puts out to tell the body to start producing the hormones associated with puberty in both boys and girls. Before puberty, children have only small amounts of a hormone called GnRH—gonadotropin releasing hormone. The hormone is released infrequently and at low amounts. When puberty starts, the body starts making more GnRH and releasing it more frequently. GnRHa treatment turns down that signal until doctors and patients are ready for puberty to begin.

Puberty usually begins within 6 months to a year after stopping GnRHa treatment. Scientists have consistently found that young people who receive GnRHa treatment for precocious puberty reach greater adult heights than those who are not treated. That is particularly true for those who experience puberty starting before age six.

Research suggests that young people receiving treatment may also experience reduced stress and stigma from the ways in which precocious puberty makes them different from their peers. However, more studies are needed before scientists will have a true understanding of the psychological effects of precocious puberty treatment.

Both short acting and long acting forms of puberty blockers are available. Long-acting forms may last for up to 2 years without a need for repeat treatment. These either take the form of long term injections or implants. Specific treatments include the histrelin implant and depot leuprolide acetate injections.

Are Puberty Blockers Safe?

Puberty blockers have been used for more than three decades to treat precocious puberty. They are generally considered to be both safe and effective. Research suggests that young people who have been on puberty blockers have normal reproductive function after they stop taking them, although young women may have an increased risk of PCOS. Data also suggests that puberty blockers don't have long term effects on bone or metabolic health. However, some scientists would still like to see research on life-long effects of these treatments before declaring them truly safe.

Of note, one of the main considerations for young people on GnRHa treatment is maintaining weight control. These drugs can be associated with weight gain and obesity. As obesity is also associated with precocious puberty, it is important to pay attention to diet and exercise and other factors that can help a young person maintain a healthy weight. However, the good news is that research suggests that in the long-term, GnRHa treatment is associated with achievement of healthy weight, at least for girls. Therefore, it should not be a major factor in deciding whether or not to begin treatment.

Sources:

Fuqua JS. Treatment and outcomes of precocious puberty: an update. J Clin Endocrinol Metab. 2013 Jun;98(6):2198-207. doi: 10.1210/jc.2013-1024.

Kim EY. Long-term effects of gonadotropin-releasing hormone analogs in girls with central precocious puberty. Korean J Pediatr. 2015 Jan;58(1):1-7. doi: 10.3345/kjp.2015.58.1.1.

Pienkowski C, Tauber M. Gonadotropin-Releasing Hormone Agonist Treatment in Sexual Precocity. Endocr Dev. 2016;29:214-29. doi: 10.1159/000438893.

Thornton P, Silverman LA, Geffner ME, Neely EK, Gould E, Danoff TM. Review of outcomes after cessation of gonadotropin-releasing hormone agonist treatment of girls with precocious puberty. Pediatr Endocrinol Rev. 2014 Mar;11(3):306-17.

Yoo JH. Effects of early menarche on physical and psychosocial health problems in adolescent girls and adult women. Korean J Pediatr. 2016 Sep;59(9):355-361.

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