Puberty occurs at different ages in different children. In fact, there is a wide range of ages at which puberty first begins. Girls usually begin to develop breasts and then pubic hair at around 10 or 11 years of age, but the range of normal is between 8 and 13 years old. Menstrual periods usually start around 12 to 13 years of age, but may occur earlier or later and still be normal. Boys usually develop enlarging testicles and then pubic hair between 11 and 12 years of age, but the range of normal is between 9 and 14 years old.
Precocious puberty means having signs of puberty (such as pubic hair or breast growth) at an age younger than normal. Early puberty causes the development of sexual traits earlier than expected, and leads to rapid bone growth that can result in short stature. Most doctors agree that a girl has precocious puberty if she develops sexual traits earlier than age 8, and a boy has precocious puberty if he develops sexual traits prior to age 9.
During precocious puberty, the hypothalamus and pituitary glands signal the ovaries (in girls) or testicles (in boys) to make female or male hormones earlier than normal.
Risk Factors for Precocious Puberty
Risk factors related to childhood cancer treatment include:
- Radiation to the head or brain, especially in doses of 18 Gy (1800 cGy/rads) or higher, including the following fields:
- Cranial (whole brain)
- Nasopharyngeal (nose and throat)
- Oropharyngeal (mouth and throat)
- Infratemporal (midfacial area behind the cheekbones)
- Total body irradiation (TBI)
- Female gender
- Younger age at treatment
If the survivor has any of the risk factors described above, or if there are signs of accelerated growth or early puberty, the following tests are recommended:
- A blood test for FSH (follicle stimulating hormone), LH (luteinizing hormone) and sex hormone (estradiol or testosterone) level
- Bone age X-ray (an X-ray that measures the developmental age or maturation of bone)
Treating Precocious Puberty
If a problem is detected, a referral may be made to an endocrinologist (doctor who specializes in hormone problems). Medications may be used to temporarily stop puberty and to decrease the rate of bone maturation. It is also important to evaluate and manage the psychological effects of beginning puberty too early. Although children with precocious puberty may have a mature physical appearance, their thoughts, emotions, and behaviors are still that of their actual chronological age.