Stop Precocious Puberty With Puberty Blockers

Precocious puberty is when a child starts to show signs of puberty earlier than is considered to be normal. For those assigned male at birth, signs of puberty before age 9 are usually considered to be precocious puberty. For children assigned female at birth, 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 can be more common in young black girls. These signs alone are not necessarily considered to be precocious puberty. Determining whether puberty is precocious can be a medical judgment call.

Little boy having fun with friends in park blowing bubbles
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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 excess childhood weight. On the other hand, there is evidence that the fact that puberty is happening earlier 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 towards puberty starting at a younger age. 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. If puberty occurs earlier in the population as a whole, those problems would be expected.

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. (Because of social expectations about gender, short stature is considered to be more of an issue for cisgender boys.)

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. Others might be best addressed with social change and an emphasis on accepting people with differences.

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 excess weight is linked to both early puberty and to all three health conditions. In other words, excess weight may cause both the early puberty and health risks. There may also be a slightly higher risk of breast cancer in those assigned female at birth who have their first period or breast development 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 before the time when puberty would normally be expected.

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. These causes are not affected by puberty blockers.

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

Puberty blockers are more commonly known as GnRH analogs 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. 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.

Research has found that young people who receive GnRHa treatment before the age of six for precocious puberty reach greater adult heights than those who are not treated. However, a 2019 meta-analysis found no such effect for cis girls receiving treatment between the ages of seven and ten.

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.

Gender Identity and Puberty Blockers

Another indication for puberty blockers is having a gender identity other than the one associated with one's sex at birth. For transgender and non-binary youth, starting puberty can be an incredibly upsetting experience. Puberty blockers are a way that doctors can give teens and their parents time to fully understand the young person's gender identity. When ready, the young person can go through puberty in their identified gender. If that's the gender associated with their sex assigned at birth, they can stop blockers and start puberty naturally. If it's not, they can be treated with cross-sex hormone therapy.

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. 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 the 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. The research is controversial on whether these drugs cause weight gain. As excess weight 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 the achievement of healthy weight, at least for cis girls. Therefore, it should not be a major factor in deciding whether or not to begin treatment.

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Additional Reading

By Elizabeth Boskey, PhD
Elizabeth Boskey, PhD, MPH, CHES, is a social worker, adjunct lecturer, and expert writer in the field of sexually transmitted diseases.