How is “normal” growth defined?
Measured in height, “normal” growth is described as growth of:
- 0 to 12 months - about 10 inches. Growth during this phase is primarily a function of nutrition.
- 1 to 2 years - about 5 inches. From the age of 1, hormonal factors play an increasingly important role in your child’s growth.
- 2 to 3 years - about 3 1/2 inches a year
- 3 years to puberty - about 2 inches a year. There is minimal difference in growth seen in boys and girls until puberty, which results in an average height difference of 4 to 5 inches between the sexes.
What causes growth problems?
Growth problems can be caused by a number of factors, including genetics, hormonal disorders, systemic illnesses and poor absorption of food. Causes of growth problems usually fall into the following categories:
- Familial short stature, a tendency to follow the family's inherited short stature (shortness).
- Constitutional growth delay, also known as delayed puberty. A child with this condition enters puberty later than average, but is growing at a normal rate. Most of these children tend to eventually grow to about the same height as their parents.
- Illnesses that affect the whole body, also called systemic or chronic illnesses, or illnesses that affect the digestive tract, kidneys, heart or lungs.
- Malnutrition. Constant malnutrition prevents a child from growing as tall as she could; a well-balanced diet generally prevents or corrects this. Malnutrition is the most common cause of growth failure around the world.
- Severe stress
- Endocrine (hormone) diseases, such as diabetes or a lack of thyroid hormones, which are necessary for normal bone growth.
- Syndromes (genetic disorders). Growth problems may be a feature of syndromes such as Cushing's syndrome, Turner syndrome, Down syndrome, Noonan syndrome, Russell-Silver syndrome and Prader-Willi syndrome.
- Growth hormone deficiency. A child with this growth disorder has a problem with the pituitary gland (small gland at the base of the brain) that secretes several hormones, including growth hormone.
- Congenital (present at birth) problems in the tissues where growth occurs.
- Intrauterine growth restriction (IUGR). This condition results from a fetus’s slow growth within the uterus. The baby is born smaller in weight and length than normal, in proportion to his short stature.
- Chromosome abnormalities. Having too many or too few chromosomes can result in health problems, including problems with growth.
- Skeletal abnormalities. There are more than 50 bone diseases that affect height and growth, many of which are genetic. The most common is achondroplasia, a type of dwarfism in which the child's arms and legs are short in proportion to his/her body length. The head is often large and the trunk is normal-sized.
- Precocious puberty. This growth disorder is characterized by an early onset of adolescence in which a child is tall for his age initially, but due to rapid bone maturity, growth stops at an early age and the child may be short as an adult.
- Genetic conditions. There are a few genetic conditions that result in tall stature, where other health problems are also present.
- Idiopathic. There are several growth disorders that are idiopathic, meaning that there is no known cause for the growth problem.
What are the symptoms of a growth problem?
The primary symptom that may indicate a growth problem is when a child grows less than two inches a year after his second birthday. Other symptoms may include:
- slow development of physical skills, such as rolling over, sitting up, standing and walking
- delayed social and mental skills
- delayed development of secondary sexual characteristics in adolescence