Kara J. Connelly, M.D.
Dr. Connelly is a board-certified pediatric endocrinologist who cares for children with a wide variety of disorders. She cares for children and adolescents with type 1 and type 2 diabetes mellitus at the Harold Schnitzer Diabetes Health Center and sees patients with other general endocrinology disorders at Doernbecher Children’s Hospital.
Puberty: Too late or too early?
You may hear this question from parents whose child appears to be going through puberty early or late. Parents may notice changes before they expect them or worry because the child’s peers are maturing more quickly. This article reviews current thinking on the age range of puberty, when to be concerned, ways to evaluate a child and when to refer if needed.
Age range for puberty
The age range for onset of puberty is different for boys and girls, and can vary by ethnic heritage. The table gives details for both sexes and several ethnic groups.
|Male or female||Ethnic group||Age range in which start of puberty is normal||Average age of puberty|
|Female||Caucasian||7 to 13 years||10 years|
|Female||African American||6 to 13 years||8.8 years|
|Female||Hispanic||7 to 13 years||9.3 years|
|Male||Caucasian||9 to 14 years||11.5 years|
|Male||African American||9 to 14 years||11.8 years|
|Male||Hispanic||9 to 14 years||11.8 years|
Signs of true puberty
Children of both sexes can develop pubic hair and adult-type body odor before the hormonal changes of true puberty occur, and these developments are not necessarily cause for concern. Testicular enlargement is usually the first true sign of puberty in boys. In 85 percent of girls, breast development is the first sign that sex hormones have become active.
When is puberty late?
Puberty is late when a child reaches the upper limit of the normal age range with no signs it has begun. This upper limit is 13 for girls and 14 for boys. If children have not developed signs of puberty by these ages, work-up or referral to a pediatric endocrinologist should be considered.
Parental anxiety and expectations
Physical development and parental expectations are often based on familial patterns and timing. For example, a mother who went through puberty earlier than average may not be alarmed to see her daughter developing breast buds at age 8.
Since the child falls within the age range for normal pubertal onset, there may be no need for evaluation or intervention.
Parents may be concerned about boys who, at age 13 or 14, are shorter and less developed than their peers are. The parents may note the absence of physical changes such as body hair, voice changes and changes in musculature prompted by testosterone. Most boys in this scenario will have constitutional delay of growth and puberty, often referred to as “late bloomers syndrome” and will have a normal (though delayed) growth spurt and pubertal development. However, careful monitoring by the primary provider is warranted, as well as specialty evaluation if signs of puberty are truly absent in a boy aged 14 or older.
Some pearls for talking with parents include:
- Discussing what specific concerns prompted the visit or questions about puberty.
- Reassuring parents if the child is within the normal pubertal age range, even if on the early or late end of the spectrum.
- Educating parents regarding the timing of pubertal events. For example, in girls, breast development typically precedes the first menstrual period by two to two and a half years.
- Asking about the pace of puberty – If the pace is accelerated, further evaluation may be warranted. A child who has breast buds at 8 followed by menarche in 6 months may need additional evaluation.
When to evaluate in depth
A child is not within the range of normal — Traditionally, breast development before age 7 in Caucasian girls and testicular enlargement before age 9 in Caucasian boys are cause for concern about precocious puberty. No breast development in girls by age 13 and no testicular enlargement in boys by age 14 are cause for concern about delayed puberty.
A child is at the limit of normal — In cases of early puberty, endocrinologists may be concerned with growth potential and the child’s capacity to handle early development from a psychosocial perspective. Estrogen and testosterone (which is converted to estrogen) cause growth plates to mature, eventually causing the pubertal growth spurt and fusion of growth plates. A child who begins puberty early may not reach his or her full height potential if the growth plates fuse early. In this case, an endocrinologist might treat the child to delay puberty and allow the child to gain height and catch up to peers in age and maturity.
However, not all children who start puberty on the early end of the spectrum become shorter than their peers. This is possible, but not assured. A specialist evaluation can help assess the possible sequelae of early puberty and stopping growth early. A bone age X-ray of the left hand can reveal whether the growth plates have matured under the influence of puberty hormones.
Are kids maturing earlier?
Some studies show that the timing of the puberty in both girls and boys is earlier than a generation or more ago. This is likely multifactorial. Possible causes include environmental factors, including a rise in childhood obesity, but there are many confounding variables.
Bone mineral density, nutrition and puberty
Estrogen and testosterone are important for development of adult bone mass, which is attained during the teen years. While bone mineral density may be lower in girls with delayed puberty compared to same-age peers, there is evidence that it increases once girls complete puberty, without long-term effects.
Insufficient nutrition can delay puberty. If a child in your practice has weight loss, poor weight gain or an eating disorder, pubertal delay would not be an unusual consequence. The differential diagnosis should include undernutrition in any child with delayed puberty (outside the normal range) and poor weight gain.
Signs of puberty: The history and physical examination
A thorough history and physical examination are invaluable in determining the timing of puberty and flagging potential problems. Ideally, a puberty examination is part of every well child’s checkup, as is height measurement with reference to the standard growth chart. Including this serves a dual purpose: children are accustomed to the examination, and the pediatrician or other primary provider has a baseline to note abnormalities, even if not noted by the parents.
|History and physical examination for puberty
|Timing of changes (age)|
|Testicular enlargement, if noted|
|“Adult-like” body odor|
|Growth spurt, if occurred – Heights of both parents to calculate mid-parental target height|
Asking parents about the age they experienced puberty is helpful. For the physical examination, Tanner staging and measuring testicular volume are useful.
When to refer to a specialist
You should feel comfortable consulting and, if necessary, referring a child for specialty evaluation if signs of puberty appear outside the age ranges described above, if the physical examination is abnormal, the velocity of puberty seems accelerated or simply if you have concerns.
A boy who shows testicular enlargement before age 9 needs urgent referral to a pediatric endocrinologist. A child with these changes is at increased risk of a central nervous system tumor causing early puberty.
OHSU Doernbecher Children’s Hospital includes specialists in pediatric endocrinology, including adolescent medicine and growth disorders. If you have questions or would like to refer a patient, please call the OHSU Physician Consult & Referral Service at 888 346-0644 toll-free or fax to 888 346-0645.Back to articles