What Is Precocious Puberty?
Precocious puberty, also known as early puberty, is when a child’s body starts to go through the change into an adult body too soon. Puberty starts on average in girls between ages 8 and 13 and in boys between ages 9 and 14.
Doctors diagnose the condition when puberty starts early and continues through growth spurts and bone maturation. We don’t really know why this happens. Girls who show clear signs of puberty and its progression before age 8 and boys before age 9 are considered precocious. It affects about 1 out of 5,000 children.
There are two types of precocious puberty:
- Central precocious puberty is more common. It’s just like normal puberty, but it happens early. The pituitary gland starts making hormones called gonadotropins. These hormones cause the testicles or ovaries to make other hormones: testosterone or estrogen. These sex hormones cause the changes of puberty, like breast development in girls.
- Peripheral precocious puberty or precocious pseudopuberty is a different condition. It's also less common. The hormones estrogen and testosterone trigger the symptoms. But the brain and pituitary gland aren’t involved. It's usually a local problem with the ovaries, testicles, adrenal gland, or a severely underactive thyroid gland.
There are other conditions that might look like early puberty to parents -- and sometimes even to pediatricians -- but aren't:
- Premature thelarche is when a girl’s breasts start to grow at a young age. It often affects girls who are just a few years old. While troubling for parents, it gets better on its own and isn’t early puberty. It doesn’t require treatment, but you should still take your child to a doctor to get their input.
- Premature pubarche is when pubic or underarm hair starts to grow at an early age. It can result from premature adrenarche, when the adrenal glands start releasing hormones early. Again, while it might seem alarming, it generally isn’t a problem. It’s also not an early sign of puberty. But because it may represent the first sign of an unusual and heavy release of adrenal hormones, your child should see a doctor.
Many experts say that on average, puberty is starting earlier in the U.S. than it did in the past. The average age of menstruation has stayed roughly the same. But studies suggest that early signs -- like breast development -- are happening a year earlier than they did decades ago.
Precocious Puberty Symptoms
The signs of early puberty and puberty are usually the same. It's the timing that differs. Signs include:
- Breasts start to grow (often the first sign)
- Menstruation (typically not until 2-3 years after the earlier symptoms start)
- Testicles, penis, and scrotum start to grow
- Voice deepening (this is usually a late sign of puberty)
Girls and boys
- Rapid height growth
- Adult body odor
Precocious Puberty Causes
In most cases, experts don't know what causes central precocious puberty, particularly in girls.
Sometimes, a medical problem triggers central precocious puberty. Causes are equally common in boys and children under age 6, especially if puberty is moving along quickly. They can include:
- Tumors and other growths, which are often benign
- Brain injury, either from surgery or a blow to the head, that affects hormonal balances
- Inflammation of the brain, sometimes from an infection
Only a small number of central precocious puberty cases in boys result from a medical problem. It’s even less common in girls.
Precocious Puberty Risk Factors
While they aren't necessarily causes, a number of things are linked to early puberty. They include:
- Gender. Girls are 10 times as likely to have central precocious puberty as boys.
- Genetics. Sometimes, genetic mutations that trigger the release of sex hormones can lead to precocious puberty. Most often, these children have a parent or sibling with similar genetic problems.
- Race. Researchers don’t know why, but on average, African American girls seem to start puberty about a year earlier than white girls.
- International adoption. One study showed that children who are adopted outside the U.S. are 10-20 times more likely to develop precocious puberty. Experts aren't sure why, but the uncertainty of the exact ages of the adopted children might bias the study results.
- Obesity. A number of studies have shown a link between obesity in young girls and an increased risk of precocious puberty. But researchers don't know how direct the tie is. Obesity doesn’t seem to be connected to early puberty in boys.
Precocious Puberty Diagnosis
To figure out if your child has precocious puberty, your doctor may:
- Go over their medical history
- Do a physical exam
- Do a blood test to check their hormone levels
- X-ray their hands and wrists to look at bone age. This tells them if the bones are growing too quickly.
If the doctor sees signs your child has precocious puberty, they’ll also run a test to see what kind it is. To do the gonadotropin-releasing hormone (GnRH) stimulation test, the doctor will give your child GnRH. Then they’ll check your child’s hormone response over time through a series of blood samples. If other hormones rise, that’s a sign of central precocious puberty. If hormone levels stay the same, that’s a sign of peripheral precocious puberty.
Precocious Puberty Treatment
The type of treatment your doctor suggests will depend on what’s causing your child’s precocious puberty.
- Watchful waiting. In many cases, your doctor won’t be able to find a cause. They may suggest watching your child for a few months.
- GnRH analogue therapy. If your child has central precocious puberty and no other conditions, the doctor may suggest GnRH analogue therapy. This is a medication your child gets once a month in a shot. It halts development while they take it. Your child will take it until they reach the normal age for puberty.
- Histrelin implant (Vantas). Your child would need minor surgery to get this implant. The doctor puts it under the skin of the inside part of their upper arm. It also delays development but doesn’t require monthly shots. The implant lasts for a year.
- Treatment of another condition. If your child has a condition that’s causing precocious puberty, treating that will usually stop the precocious puberty, too.
Precocious Puberty Complications
For kids, early puberty can cause physical and emotional problems. They include:
- Short stature. While kids with precocious puberty are often tall for their age, some wind up short as adults. Why? Once puberty is over, growth stops. Since precocious puberty ends earlier than normal puberty, these kids stop growing at an earlier age. The result may be a shorter height than they would have otherwise had.
- Behavior problems. Some studies have found a link between early puberty and behavior problems, particularly in kids with developmental delays. But other experts say the proof is weak.
- Early sexual activity. Although parents might worry, there's no strong evidence that kids with early puberty are more likely to be sexually active at a younger age.
- Stress. Even when it's happening to average 12-year-olds, puberty can be a confusing time. It can be all the more stressful for younger kids with early puberty. They might feel awkward about looking different from their peers. Early menstruation can be unsettling for girls who are age 9 or younger -- or who are developmentally delayed. Parents can help by teaching their kids what changes they should expect.
- Other risks. Some studies have found a link between early puberty in girls and a slightly increased risk of breast cancer later in life. But the evidence isn’t clear. We need more research to be sure.
Tips for Parents
As a parent, it's easy to worry about early puberty. There's no doubt that you should take any signs seriously. If your child shows signs of early puberty, their doctor may suggest they get checked out by a pediatric endocrinologist.
But that doesn’t mean kids and their parents should view precocious puberty as a fearful medical diagnosis.
Here are a few other things to remember:
- Symptoms that might seem like early puberty are often unrelated and clear up on their own.
- When a doctor and parents decide treatment is necessary, it usually works well.
- Most kids with signs of early puberty do fine, medically, psychologically, and socially.