Most nine-month-old babies can sit up by themselves, copy sounds, and play games like peek-a-boo, according to developmental milestone guidelines from the Centers for Disease Control and Prevention (CDC). But does “most children” mean almost all, or just more than half? Does “can” mean that they demonstrate these abilities often, or every once in a while? Developmental milestones are a key part of pediatric visits for children under five years old, allowing parents and pediatricians to “act early” if a child needs more support, but there is actually little data on what proportion of children reach milestones at different ages.
A new Boston University School of Public Health study provides more specific data on what is typical behavior at different ages—finding that, for some of the CDC guidelines, “most children” can mean over 99 percent or barely half.
For example, while the CDC says to “act early” if a nine-month-old doesn’t play games like peek-a-boo, the study finds that as many as one in ten children haven’t reached that milestone at that age, and only 49 percent demonstrate the behavior “very much.”
“The CDC guidelines are just that: guidelines,” says study lead author Dr. R. Christopher Sheldrick, research associate professor of health law, policy & management. “Parents should know that medical guidelines are frequently updated based on new information. In the meantime, parents should consider advice from a range of sources and ask their pediatric providers if they have concerns.”Friday Letter Submission, Publish on November 29