What Parents Need To Know About Growth Spurts

It’ll happen almost overnight. Your pudgy baby will unfurl into a lanky, pimply adolescent. Pubescent gears will be turning, hormones flooding their bodies, but that’s all under the hood. What you’ll notice first are the two telltale signs of puberty: body odor and a growth spurt.

“Everybody has a growth spurt, when the growth rate more than doubles over a year or two,” Dr. Alan Rogol, a University of Virginia pediatrician who studies growth at puberty, told Fatherly. “It’s always the same. What’s problematic is when it occurs. A little girl of 9 may have her growth spurt early or a boy may not have it until he’s 15 or 16, and he’s left behind by his peers.”

The word “growth spurt” is more slang than medical terminology, but it roughly means “a period in which the growth rate increases rapidly.” In that sense, we experience a handful of growth spurts throughout our lives. “The first growth spurt is in utero,” Rogol says. “It’s an enormous growth spurt that occurs in the first half of pregnancy, from two cell up to the size of a baby.” Children also grow rapidly in great spurts until age two, but then taper off and begin growing at a constant rate of about two inches per year. “Childhood growth is boring,” Rogol says.

But when clinicians talk about a growth spurt, they usually mean the big one that comes with puberty. For girls, the pituitary gland begins pumping out estrogen and growth hormone at around age 11, kicking off a period of growth that ends at around age 19, when the ends of the long bones close off. Boys experience a similar growth spurt, but it starts and ends a year or two later than that and testosterone, rather than estrogen, runs the show alongside growth hormone. Girls will grow about 3 inches per year during this period; boys will grow about 4 inches per year.

Alas, puberty seldom goes as planned and some children wait for a growth spurt that never seems to come. In extreme cases, this could be due to pituitary disease, ovarian disease, testicular disease, or a long history of taking medications like prednisone for severe asthma. Parents and children may also choose to use puberty-blocking drugs, which can delay puberty until the child has affirmed one gender or another. Those would also delay a growth spurt.

“Even with very bad malnutrition, people still grow a little,” Rogol says. “To really keep a growth spurt in abeyance, it’s usually a drug, a very severe illness, or a significant hormonal disease in which the pituitary gland doesn’t make growth hormone.”

In most cases, however, a delayed or diminished growth spurt during puberty is no cause for alarm. Rogol suggests parents keep a copy of their children’s growth curves and, if they notice that their children are significantly shorter than their peers, ask their pediatrician for advice. If the physician suspects a delay, he or she will likely administer a bone age film test (essentially an x-ray of the child’s hand) which helps doctors estimate biological age. “If the biological age is a fair amount behind the calendar age, that sort of explains why the kid is delayed in his or her growth,” Rogol says. “And then one would essentially wait for the growth spurt.” Older children who have waited long enough may be sent to an endocrinologist for further testing.

The most likely diagnosis is, in fact, parents and children who have unrealistic expectations of a growth spurt. “The vast majority that have delayed growth don’t have a pathological diagnosis,” Rogol says. “If mommy and daddy are less than five feet tall, don’t expect your kid to be 5’10.”

“Scottie dogs make Scottie dog puppies. Great Danes make Great Dane puppies.”