Share this page

Health Library


While most girls will get their first period around age 12, the range can run from age 8-16. Most of these girls are normal by biological standards, because puberty is a complex process of brain, body, and hormonal development. Still, there appears to be a trend toward precocious puberty mainly in girls and in some boys. Precocious puberty is the clinical term for those who experience abnormally or unusually early puberty.

Defining Normal Puberty

Every child is unique. When a child begins puberty depends on a variety of factors, including family history, ethnicity, and nutritional status.

Although there are several changes in the body, the changes usually occur in a specific order. For example, girls may see an increase in body fat and breast growth while boys experience testicular and pubic hair growth.

Until recently, normal puberty was thought to begin between ages 8 and 14 in girls and between 9 and 12 in boys. But, recent research has found that puberty occurs as early as age 6 in girls of certain ethnic backgrounds.

Rare Causes of Early Puberty

In rare cases, especially when pubic hair is seen in children as young as 5 years, precocious puberty can be caused by tumors of the adrenal gland, ovaries, or brain. It is also seen in those with rare genetic disorders, like McCune-Albright syndrome. While the appearance of pubic hair in such a young child warrants a visit to the pediatrician to rule out any serious causes, it may be just another variation on the norm.

Growth and Puberty

When puberty comes too early, it can affect growth. By late puberty, most children have reached 95% of their adult height. When puberty starts and ends too early, the sex hormones that help harden bones can end their growth too soon. Other problems may surface later in life. For example, the earlier a woman starts menstruating the more at risk she is for serious health conditions, such as breast cancer.

If tumors or other serious causes of precocious puberty are ruled out, and if a child's doctor believes the progress of puberty could harm their growth, hormone agonists can cancel the hormonal domino effect and delay puberty until a more optimal time.

The Mystery of Puberty

Scientists and clinicians would like to clarify what is normal for the onset of puberty, but the issue is clouded by the controversy of how puberty begins. The process is an intricate interplay of brain activity that leads to hormonal secretion. While experts can name some of the hormones involved in puberty, they do not know the triggers.

Does Obesity Affect Puberty?

Studies have looked at the effect of increased body mass index (BMI) on earlier onset of puberty. One study found that the BMI in pubertal 6-9 year old white girls was markedly higher than the BMI in prepubertal girls of the same age. A smaller difference was noted for African American girls.

The relationship between obesity and early puberty is not clear-cut, however. Multiple factors are likely involved in the development of precocious puberty. Studies are under way to look at these potential contributing factors.

RESOURCES:

Family Doctor—American Academy of Family Physicians
http://familydoctor.org

Healthy Children—American Academy of Pediatrics
http://www.healthychildren.org

CANADIAN RESOURCES:

Caring for Kids—Canadian Paediatric Society
http://www.caringforkids.cps.ca

Health Canada
http://www.hc-sc.gc.ca

References

Ahmed ML, Ong KK, et al. Childhood obesity and the timing of puberty. Trends Endocrinol Metab. 2009;20(5):237-242.

Chumlea WC, Schubert CM, et al. Age at menarche and racial comparisons in US girls. Pediatrics. 2003;111:110-113.

Kaplowitz PB, Oberfield SE, et al. Reexamination of the age limit for defining when puberty is precocious in girls in the United States: Implications for evaluation and treatment. Pediatrics. 1999;104:936-941.

Kaplowitz PB, Slora EJ, et al. Earlier onset of puberty in girls: Relation to increased body mass index and race. Pediatrics. 2001; 108:347-353.

Menstrual history. BreastCancer.org website. Available at: http://www.breastcancer.org/risk/factors/menstrual_hist. Updated November 13, 2013. Accessed February 3, 2015.

Midyett LK, Moore WV, et al. Are pubertal changes in girls before age 8 benign? Pediatrics. 2003;111:47-51.

Muir A. Precocious puberty. Pediatrics in Review. 2006;27:373-380.

Parent A, Teilmann G, et al. The timing of normal puberty and the age limits of sexual precocity: variations around the world, secular trends, and ranges after migration. Endocr Rev. 2003;24(5):668-93.

Precocious (early) puberty in children. Boston Children's Hospital website. Available at: http://www.childrenshospital.org/conditions-and-treatments/conditions/precocious-early-puberty. Accessed February 3, 2015.

Precocious puberty. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated September 30, 2014. Accessed February 3, 2015.

When puberty starts early. American Academy of Pediatrics Healthy Children website. Available at: http://www.healthychildren.org/English/ages-stages/gradeschool/puberty/pages/When-Puberty-Starts-Early.aspx. Updated January 8, 2015. Accessed February 3, 2015.



Last reviewed February 2015 by Michael Woods, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

Baptist Flame

Baptist Health Foundation

Find A Doctor

Services

Locations

Baptist Medical Clinic

Patients & Visitors

Learn

Contact Us

Physician Tools

Careers at Baptist

Employee Links

Online Services

At Baptist Health Systems

At Baptist Medical Center

close ×