08 Jul Delayed Puberty
Delayed Puberty is a common concern for young people and their parents.
Read on to learn more about delayed puberty and if you or your child should be concerned about growth.
I have been asked numerous times in my clinic in several different ways, “Is my child done growing?”
Puberty is the time for growth and development from childhood to adolescence to adulthood. The start of puberty can vary based on sex, race, genetics, and nutrition. What seems like an easy question to answer actually takes several factors to provide the best guidance.
Related info: “How Tall Should I Be?”
Potential final adult height can be estimated by mid-parental height.
For girls: subtract 13 cm from fatherʼs height and average this number with motherʼs height.
For boys: add 13 cm to motherʼs height and average this number with fatherʼs height.
Delayed Puberty: Absence of the first signs of pubertal development beyond normal range. For girls, this is absence of breast buds by 12 years. For boys, absence of testicular enlargement by 14 years.
• Hypogonadism: Impaired function of the gonads (female = ovaries; males = testes).
• Primary Hypogonadism: Your brain works and sends signals to your gonads, but your gonads donʼt work.
• Secondary Hypogonadism: Your gonads are functional, but your brain is not giving them the signal to work.
Delayed Puberty: Role of the Hypothalamic-Pituitary-Gonadal (HPG) Axis
The body works in a series of positive and negative feedback mechanisms. When the body is in need of a certain hormone, the brain receives positive feedback signals to start the downstream production. When there is enough or an excess amount of hormone produced, the brain receives negative feedback signals to stop or decrease production.
The hypothalamus, which is located in the brain, produces Gonadotropin Releasing Hormone (GnRH).
GnRH travels in the brain to the anterior pituitary gland, which stimulates production of Folicle Stimulating Hormone (FSH) and Leutinizing Hormone (LH).
FSH and LH then stimulate cells in the gonads to produce sex hormones.
• In males, the testes produce testosterone
• In females, the ovaries produce estrogen
These sex hormones are what stimulate pubertal changes and skeletal maturation.
During puberty, both boys and girls undergo a series of physical changes. Grading and measuring of these changes occurs during routine physical exams using Tanner Stages. Generally, the start of each stage can vary, but can have an expected age range.
Girls tend to start puberty at a younger age than boys.
- The first stage is breast bud development usually by 9-10 years
- Peak height velocity (fastest time of growing taller) usually occurs by 11 years
- The first menstrual period (called menarche) tend to be 12-13 years
- Puberty tends to end by 14 years
For boys, they tend to start puberty at a later age than girls.
- The first stage is increased testicular size with small amount of pubic hair usually by age 11-12 years
- Peak height velocity (fastest time of growing taller) tends to occur by 14 years
- Sperm production tends to occur between 14-15 years
- Puberty tends to end by 15 years
Causes of Delayed Puberty
Delayed puberty occurs in about 2-5% of adolescents. Approximately 85% of cases are due to secondary hypogonadism and 15% are due to primary hypogonadism. This discussion will now focus on secondary hypogonadism.
In secondary hypogonadism, there is limited signal release from the brain which can be due to various reasons:
- Inadequate caloric intake, malnutrition, malabsorption
- Mismatch of energy intake and expenditure (not enough coming in, too many calories burned)
- Stress leading to higher cortisol levels
- Chronic disease such diabetes, cystic fibrosis, inflammatory bowel disease, lupus, etc.
Related Topic: Can certain sports cause delayed puberty?
Sports such as gymnastics and figure skating have been associated with delayed puberty, especially in female participants. It is uncertain if this is due to that calorie mismatch, coaches favoring athletes with delayed puberty, or a combination. Studies show that eventually these athletes will catch up and reach predicted adult heights, sometime after retiring from their sport. If you have an athlete with delayed puberty, do seek medical evaluation to ensure the best chances for full growth.
Constitutional Delay of Growth and Puberty
Also known as the “Late Bloomer”, this accounts for approximately 50% of the causes of delayed puberty. On height and weight growth curves, these individuals tend to be in the lower than expected ranges for many years. They will usually have mothers with menarche after 14 years or fathers with growth spurts at 15-17 years. The final adult height will be within the lower normal range.
Arguably, the most important part of this diagnosis is obtaining a detailed history and physical exam. History would include:
- Details of any pubertal development
- Nutrition – which includes types and amount of food and beverage intake
- Exercise – including type and amount
- Chronic illnesses
- Family history of late bloomers
Physical exam should include serial measurements of height, height vs arm span, and Tanner Stages.
Ordering of lab testing is guided by the history and physical exam, but generally is not needed in healthy patients. Blood work may show low LH/FSH and estradiol/testosterone levels, but otherwise all other findings will be normal. Order an x-ray of the right hand to study skeletal maturation (also known as bone age). “Late bloomers” will have a bone age that is delayed approximately 2 years compared to their true age. In these cases, the child will grow to full expected adult height, just slower than most of their peers.
Delayed puberty: Wait or treat?
The mainstay therapy is watchful waiting. Many patients can develop anxiety while watching their friends grow and develop faster than them. It is crucial to discuss concerns with medical providers to ensure adequate support to help cope with these feelings.
Depending on the circumstances, there are potential medical treatments. Consider giving girls low dose oral estrogen or boys given monthly testosterone injections for 4-6 months. Monitor for continued growth when treatment ends. Studies have shown these therapies may help patients reach their final adult height sooner. However, these treatments ultimately do not change what the final adult height will be.
It is important to remember that in most cases of delayed puberty, kids will eventually catch up.