Check-up season is winding down and I’ve seen a ton of kids of all ages preparing for a new school year. For most children, growing well is taken for granted. Unless you are super tall or super short, you feel pretty typical when you are a kid. When a child is quite short parents are often concerned and sometimes the older child is wondering if he’s normal or if he’s ever going to grow. Usually I can reassure parents and kids alike about growth but occasionally a short child warrants medical assessment.
Height is determined mostly by your genes. If you have tall parents you are likely to be tall and if you have short parents you are likely to be short. Sometimes though, children will be shorter than expected based on parents’ heights at least until puberty hits. If you have a short child but he’s growing about 2 inches each year (before puberty) then chances are your child doesn’t have a medical problem. Most of the time these shorter kids will end up going into puberty later than their peers and end up even taller than average. These late bloomers often have a parent or close relative who was a late bloomer too. If you think back to your own middle and high school years and everyone else finished puberty long before you did, you are more likely to have a child who is shorter than expected during the prepubertal years who ultimately finishes puberty and is normal or even tall.
Because late bloomers continue to grow 2 inches per year until pubery hits and because they go through puberty 2-3 years later than average, they have the chance to grow 4-6 inches more than the typical kids who goes into puberty at the usual time and as a result, even though they start out shorter than their peers they often end up taller in the long run. One way to tell if your child is a late bloomer is to have a bone age done which will show that his bones are actually younger than his age. Sometimes bone age and chronologic age are the same in which case your child is genetically short and won’t make up for it at puberty. Here’s an example: Your son is 10 and at the 5th percentile for height (which means that 95% of other 10 year old boys are taller than he is). And your child’s actual height is that of the typical 8 year old boy. If you get a bone age and his bones are 8 years old he will go through puberty later (when his bones are 12 or 13 years old but when he is 14 or 15 years old) and he will likely be average or above average in height in the long run. If the bone age is 10 years old (matching his chronologic age) then your son is destined to be shorter than average and will go through puberty at the usual time.
Very rarely short height is due to a medical problem like low thyroid or growth hormone deficiency and these kids stop growing for a stretch of time. They don’t grow 2 inches or so per year and instead seem to stall out. If your child is short and growing a couple of inches per year, you may want to talk to your healthcare provider about doing a bone age so you can predict if your child will ultimately be short or is destined to be a late bloomer.