Your Baby’s Head Is Probably Not Gigantic
In the first days of birth of new parents, going to the doctor to check the baby can seem like a grand event. Aside from the excuse to put on your pants and hang out with real adults, this is an opportunity to finally get quantifiable data about this tiny creature, whose existence, associated with food, sleep and pooping, can seem so messy. The big test is when the nurse takes your baby’s measurements. “How is my baby growing?” – dads and moms ask impatiently. The numbers they hear can surprise, amuse, and sometimes disturb them.
“She has a huge head,” my sister tells me as she talks about her newborn baby weekly. “Ninety percentile”.
“Yes!” my dad says. “She will become a genius!”
We will not dream of crushing here, but the conversation seems to be ordinary. On Facebook, I often see parents posting the results of their child’s most recent check-up. Topic: medium weight, huge heads. Ninety-fifth percentile. Ninety-ninth percentile. A number that is outside the scope of the graphs . A relative told me that from the moment her son was born until his monthly check-up, his head “shot up from 66% to 98%.” (My own child did not have a particularly remarkable infant head size – it was about 60%.)
Writer Ruth Graham noticed that a curious number of her friends seemed to show off their babies’ large or fast-growing shoes. “I felt like I was living on Lake Wobegon, like a boob, where the heads of all the children were above average,” she writes. So she started digging. She found that this phenomenon was due to inaccurate head circumference standards .
Infants born in the United States are surveyed based on a curve published by the World Health Organization . Graham cites research by Carrie Damont, assistant professor of pediatrics at the University of Pennsylvania, which found that the curve does not represent the actual heads of infants in the population:
What Damont discovered when she started doing it will crush the pride of any parent who enjoys showing off their offspring’s colossal skull. She started with a dataset that included head measurements of 75,000 pediatric patients in three states and compared those measurements to a WHO chart. If diagram WHO accurate, then 5 percent of babies should be above the 95 th percentile, 10 percent of the – above 90 percentile and so on. This is not true. According to the WHO chart, from birth to two years of age 14 percent of infants were above the 95 th percentile.
For 2 years in 18 percent of the children were above this threshold value, which means that in fact it is not the 95 th percentile, and 82 th.
The inaccuracies stem from the fact that we are using a universal chart based on measurements of babies in several countries, although in reality, as Graham explains, “head size does not seem to differ significantly between populations, possibly due to genetic or epigenetic variation.” … To further confuse the situation, doctors plot each dimension on a different growth chart: one from the Centers for Disease Control and Prevention (CDC).
The implications of this, of course, go beyond what a disproportionately large number of parents are talking about the potentially giant brains of their children on Facebook. The purpose of head circumference growth curves is to identify children who may require additional testing due to a large head called macrocephaly, or a rapidly growing head.
Damont found that when using CDC curves, the percentage of children diagnosed with macrocephaly changed with age. “A fifth of the expected number of one-month-olds and 2.5 times the expected number of one-year-olds were classified as having macrocephaly or above the 95th percentile, ” the report said . “Many of these older infants above the 95th percentile may have had unnecessary follow-ups and referrals, and their parents may have been unnecessarily worried.”
Head circumference measurements are important – a friend of Heather tells me that measuring her son’s head during his one-year visit was a “saving grace” in the discovery of hydrocephalus , a condition that is estimated to affect one or two children in 1,000. these routine measurements, everything would be very bad, ”she says.
However, we need a better measurement system.