Your child's growth may be affected by a range of factors, and several reasons could explain why they're not growing at an expected rate. Here are some of the more common reasons:
Genetics
There are many ways that genetics can affect growth in a child. Here are some examples:
If parents or other family members are shorter, it's common for a child to grow at a slower rate than their peers. This is often referred to as familial short stature, and it's usually not indicative of an underlying problem. The child might be shorter than average simply because of their genetic makeup. However, sometimes a parent was shorter than expected when they were finished growing, because of an undiagnosed reason as a child, and that has been passed along to their child.
For instance, Turner syndrome is a condition in women where one of the X chromosomes is missing or partially missing. This syndrome often leads to a shorter height because it disrupts normal growth and development.
Bone and skeletal diseases can also cause short stature. These conditions may change stature through their effects on bone growth. One such condition is achondroplasia, a form of short-limbed dwarfism, where there is a problem with the way bones grow.
SHORT syndrome is a rare genetic disorder that impacts many parts of the body, leading to short stature among other symptoms. It results from mutations in the PIK3R1 gene. This gene is involved in several cell activities including cell growth and division, movement of cells, and production of new proteins. Most people with SHORT syndrome are small at birth and gain weight slowly in childhood. As adults, they tend to have short stature compared to others in their family.
It's important to note that short stature is defined differently depending on various factors such as population, age, and gender. The U.S. Food and Drug Administration (FDA) defines short stature without an underlying cause (idiopathic short stature) as when a child's height is two standard deviations below the mean (a height that is essentially at or under the 1st percentile for age and gender), or when the predicted height is 5’4” or under for a boy is; or 4’11” or under for a girl.
Constitutional Growth Delay: Children with this condition are shorter than average but grow at a normal rate. They typically have a delayed "bone age," which means their bones mature at a slower rate than their peers. More commonly people know this as being a “late bloomer,” because they also tend to reach puberty later, resulting in a below-average height in early teenage years. However, they usually catch up with their peers in adulthood.
Hormonal Conditions: Conditions such as hypothyroidism or growth hormone deficiency can cause delayed growth. Hypothyroidism, where the thyroid gland is underactive, disrupts the release of hormones needed for normal growth. Growth hormone deficiency prevents the body from maintaining a healthy rate of growth.
Systemic Diseases: Illnesses affecting the entire body, such as malnutrition, digestive tract diseases, kidney disease, heart disease, lung disease, diabetes, or severe chronic stress, can cause growth problems.
Nutrition: When a person's intake of energy and/or nutrients is insufficient to meet their daily requirements it can stunt their growth. Stunting is a result of chronic or recurrent undernutrition, which may be associated with poor quality food options, frequent illness, and/or inappropriate eating. Inadequate intake of vitamins and minerals (micronutrients) can cause malnutrition.
Additionally, during adolescence, nutrition plays a formative role in the timing and pattern of puberty, which influences adult height, muscle, and fat mass accrual. Nutritional deficiencies during this phase can hinder these processes, leading to suboptimal growth and development.
If you suspect your child isn’t growing at a normal rate, make an appointment with their doctor. The doctor may assess their general growth rate and consider their overall health, your family's health history, and any potential symptoms of underlying conditions. Depending on the cause, treatment options could range from hormone therapy, nutritional therapy, treatment for systemic diseases, or even a combination of treatments.
If your child’s doctor is concerned that there may be a problem, a pediatric endocrinologist will be considering all of the reasons listed above and should be advising you on how you can support your child in addressing these possible concerns.