Growth and development go hand-in-hand. In fact, normal growth is an important indicator of your child’s overall health and wellbeing as he or she ages. Growth is a dynamic process that should be evaluated at every well visit your child has with the paediatrician. So, as a doctor checks your child’s eyes, ears, heart, and belly, they will also check on the progress of your child’s weight and height over time to gain important information about your child’s health.
It’s important to understand the difference between height and growth. Height is simply how tall or short your child might be at any given point in time. Your child’s growth is the dynamic measure of how your child’s height changes over time, and is used to determine any health or nutritional abnormalities, or underlying growth disorders.
Normal growth is when your child’s height measurements over time, fall within the average range of what is expected for his or her age. There is a natural variation in all children’s height, and children in the same family may be shorter or taller than one another. The important thing is that when their height is taken accurately and plotted over time, they should stay on approximately the same percentile on Australian and New Zealand standardised growth charts.
Parents often worry about how short or tall their child will be, so it is always a good idea for them to have some idea of what to expect. A quick and easy way to figure an approximate target for your child’s ultimate height is to use the following formula:
- If your child is a boy, you can add 13 cm to his mother’s height in centimetres and then add this number to his father’s height in centimetres. Take this number and divide it by 2 to get an approximate height target.
- If your child is a girl, subtract 13 cm from her father’s height and then add this to her mother’s height in centimetres. Take this number and divide it by 2 to get an approximate height target.
Again, this gives you an approximation of what the genetic height potential is for your child.
It may also help to know that children have a predictable rate of growth, which is known to endocrinologists as the “rule of halves.” Here’s how it works: let’s say a child is born at 50 cm long; during the first year of age, that child will grow about half of that amount, or 25 centimetres The next year, that child will grow half again, which is 13 centimetres. One more year after that, the child will grow half again, which is 6 centimetres. From that point on (at 3 years), most children grow about 5 centimetres per year until puberty, which usually involves a growth spurt of 10-15 centimetres for boys and 8-13 centimetres in girls in one year. After puberty, sex hormones cause the growth plates in the body to mature; at which point growth slows down.
On the whole, there may be occasional variations in this rule of halves, as children grow in a step-wise fashion, which means in spurts, rather than in a linear fashion. However, if a child over 2 years of age is persistently growing less than 5 centimetres a year over time, or consistently growing more than 5 centimetres a year over time, this may be an indication of a health problem. Ask about how much height your child has gained since the last doctor’s visit and discuss any growth concerns you may have.
Too little or too much growth can be a sign of a medical problem. This can include conditions such as nutritional deficiencies, infections, genetic diseases, hormonal disorders, or diseases of the liver, kidneys or gastrointestinal tract. A series of tests and a physical examination with a thorough medical and family history can be used to rule out these and other disorders. Most children with suspected growth abnormalities are referred to an endocrinologist (type of doctor that specializes in diseases related to hormones and growth) for further evaluation and treatment.
If a child has a growth disorder, that causes them to be shorter than normal, treatment may help them grow in height, especially when the problem is identified early enough. In fact, the earlier a growth deficiency is detected, a treated child has a greater chance to regain normal height and catch up to his peers in growth.
Keep Track At Home
Parents may detect a growth abnormality when their child first enters school because it is often the first time that a parent sees their child’s height in comparison to other children of the same age. But, generally speaking, growth abnormalities starts before school age, so tracking your child’s growth at home as soon as your child is old enough to stand can help identify any growth issues.
Measuring your child at home is an easy way to monitor your child’s growth. Here’s how:
- Put a book flat on the wall and then bring it down level until the book rests on top your child’s head
- Make sure his or her eyes are looking straight ahead and are roughly even with his or her ears
- Mark the height on the wall or use a growth digital growth chart and enter the height each year
The important thing is to use the same technique every time you measure your child’s height. Keep track of how much change occurs each year, and be sure to share this information with the paediatrician.
Remember, though, that no two kids are exactly the same—even siblings may be different in height and weight. As long as their growth is consistent over time and it is within the average range for their age, children have a right to be short or tall. As long as they are healthy and on target, whatever height they are is perfectly normal.
José Cara, M.D., is an endocrinologist, and a Vice President of Endocrinology at Pfizer, Inc.