Puberty is the time when a child's body starts to change to an adult's. Normally, these changes begin in girls when they're between 8 and 14 years old. In boys, they start between the ages of 9 and 15. This wide range in age is normal, and it's why kids may develop several years earlier or later than many of their friends.
Sometimes, though, kids pass this normal age range for puberty without showing any signs of body changes. This is called delayed puberty.
Doctors usually can help teens with delayed puberty develop so they can catch up with their peers.
These changes are caused by the sex hormones testosterone (in boys) and (in girls) that their bodies start making in much larger amounts than before.
What Happens in Delayed Puberty?
Signs of delayed puberty in boys include:
the penis and testicles not starting to grow larger by age 14
genital growth that takes longer than 5 years
short stature compared with their peers, who now are growing faster
In girls, signs include:
no breast development by age 14
not starting to menstruate within 5 years of when breasts start to grow or by age 16
What Causes Delayed Puberty?
Delayed puberty, which is more common in boys, can happen for different reasons.
Most often, delayed puberty is a pattern of growth and development in a family. A child's parents, uncle, aunt, brothers, sisters, or cousins might have developed later than usual too. This is called constitutional delay and usually doesn't need any treatment. These "late bloomers" in time will develop normally, just later than most of their peers.
Some medical problems can cause delays in puberty:
Some kids and teens with chronic illnesses like diabetes, cystic fibrosis, kidney disease, or even asthma may go through puberty at an older age. That's because their illnesses can make it harder for their bodies to grow and develop. Proper treatment and better control of these conditions can help make delayed puberty less likely.
Being malnourished — not eating enough food or not getting good nutrients — can make someone develop later than peers who eat a healthy, balanced diet. This can happen because of food insecurity, as well as disordered eating or excess physical activity. Teens with the eating disorder anorexia nervosa, for example, often lose so much weight that their bodies can't develop properly. Girls who are extremely active in sports may be late developers because their level of exercise keeps them so lean. Girls' bodies need enough fat before they can go through puberty or get their periods.
Chromosome disorders can delay puberty in some people. Chromosomes are made up of DNA that contain our body's construction plans. So when they have problems, it can affect normal growth processes. For example:
Turner syndrome is when one of a female's two X chromosomes is abnormal or missing. This causes problems with how her body grows and makes sex hormones, and how her ovaries develop. Women who have Turner syndrome are shorter than normal, may not go through puberty in the usual way, and may have other medical problems. Sometimes, puberty starts at a normal time, and then stalls or stops after a few years.
Klinefelter syndrome is when males are born with an extra X (XXY instead of XY). This condition can affect testicular function and sexual development. These boys usually are tall for their age, might have learning problems, and may have other medical problems. Puberty usually starts at a normal time, but then stalls.
How Is Delayed Puberty Diagnosed?
If a boy or girl hasn't shown signs of puberty as they move into the teen years, doctors will:
Do an exam.
Take a medical history, including whether others in the child's family had a similar growth pattern.
Ask about any medicines the child takes.
Check the growth chart to see if there's a pattern that points to a problem.
They also might:
Order blood tests to check for thyroid, pituitary, chromosomal, or other problems.
If doctors find a problem, they usually refer families to a pediatric endocrinologist, a doctor who specializes in treating kids and teens who have growth problems, or to another specialist for more tests or treatment.
How Is Delayed Puberty Treated?
Often, the doctor will find no underlying physical problem. Most kids with delayed puberty are just developing a bit later than average and will catch up.
Some late bloomers struggle with waiting for the changes of puberty to start. So doctors may offer hormone treatment:
Boys might get a short course of treatment with (usually a monthly injection for 4–6 months) to get the changes of puberty started.
Girls might get low doses of estrogens for 4–6 months to start breast development.
After treatment ends, the teen's own hormones usually take over to complete the process of puberty. If they don't, the doctor will discuss long-term sex hormone replacement.
How Can Parents Help?
It can be hard for kids and teens to watch their friends grow and develop when the same thing's not happening to them. They might get teased at school or not be able to play a sport they like. Their body image and self-esteem can suffer.
A healthy body image comes from accepting your body, liking it, and taking care of it. To boost a child's body image:
Engage them in activities that they enjoy and can master.
Help them get plenty of sleep and eat a healthy diet.
Make sure teens are active every day.
Reassure them that their growth and development is normal for them, and they will catch up with their peers.
And be a good body-image role model yourself. When a parent talks about their body in positive ways and takes good care of it, kids pick up on this and do the same for themselves.
Remind your child that a late start to puberty is a problem that usually gets solved, and that in time they will catch up. But if your child seems depressed or has school or other problems, finding a counselor or therapist to talk to can help.