Changes to the federal government’s developmental milestone checklists have some experts concerned about potential delays to early intervention.

The Centers for Disease Control and Prevention released revised versions of the checklists in February as part of its “Learn the Signs. Act Early.” campaign, which was first introduced in 2004 in partnership with the American Academy of Pediatrics. The checklists are commonly used by pediatricians to flag children in need of further screening for autism or other developmental disabilities.

The biggest change in the new versions raises the rate of expected behaviors from 50% to 75% of children of the same age for targeting potential interventions. In one example, children who have not started to talk by 12 months (the age in the previous milestone checklist) now wouldn’t trigger concern until 15 months, the age when 75% of children have reached the milestone.

The change should increase the number of children referred for further evaluation, said Dr. Paul Lipkin, a developmental pediatrician at the Kennedy Krieger Institute who worked on the checklist revisions.

Using the 50%, or average, threshold in the past “led to delays in diagnoses as clinicians and families often chose a ‘wait-and-see’ approach,” Lipkin said.

But placing milestones at a later age means interventions will be pushed back even later than they are now, according to the American Speech-Language-Hearing Association. The group publishes its own set of guidelines for developmental milestones but uses a wider age range to stress a more individualized approach. The revised CDC checklists could “slow and/or inhibit referrals for early intervention” which is critical for optimum outcomes, according to the group.

“Our speech-language pathologists on staff will monitor and members will also provide us with information if they experience any impact on their services including referrals,” said Lemmietta G. McNeilly, the association’s chief staff officer of speech-language pathology.

Leaders from the association met with the CDC and the American Academy of Pediatrics in March to discuss their concerns with the changes, primarily regarding the potential for delayed intervention, McNeilly said. She advises parents to rely on their instincts about their child’s development rather than a set timeline or checklist and to feel comfortable seeking an evaluation from a speech-language pathologist if there are any concerns.

If only the CDC checklists are followed, “a child with delays may not receive an assessment or recommended intervention until they have more significant delays and may be at risk of entering kindergarten with delays that will impact their school readiness to learn,” McNeilly said. “The goal is to intervene early so that children will enter kindergarten ready to learn.”

Other critics of the revised checklists voiced concern that the changes may have been made in response to the pandemic, to lower standards for development because of the potential impact of masking or isolation among children and caregivers.

But the changes were initiated and reviewed before the start of the pandemic in response to concerns of parents and pediatricians, Lipkin said, “to provide a clearer, up to date, and more accurate set of milestones rooted in good research.”

“I know that many parents have concerns about their children’s development because of pandemic disruptions,” Lipkin said. “I encourage parents to use these updated milestones as conversation starters with their children’s pediatric providers, especially if they observe any delays in development.”

The milestones were revised for three reasons, according to the CDC: to align the checklists with the ages of the American Academy of Pediatrics’ recommended well-child doctor visits, to assign milestones to ages when most children would be expected to meet them and to address confusion about similar milestones across ages.

In addition to meeting with the American Speech-Language-Hearing Association, representatives from the CDC and the American Academy of Pediatrics met with the American Physical Therapy Association in March regarding the changes to the milestones.

Leaders from the physical therapy association called for the meeting over concerns about the CDC’s removal of crawling from milestone checklists. The meeting was “productive,” according to a spokeswoman for the association.

“The removal of the crawling milestone was not due to its unimportance but rather because the scientific literature is inconsistent in how it defines ‘crawling’ and at what age it should be achieved,” said Colleen Fogarty.

The association and the CDC agree that “independent mobility is an important component of a child’s healthy development,” Fogarty said.

The updated checklists include independent mobility markers for each age, including walking along furniture by 12 months.

The CDC’s milestone checklists should not be used as screening tools and are not intended to determine whether a child should qualify for services, said Karen Hunter of the CDC’s National Center on Birth Defects and Developmental Disabilities. The checklists should be used to open the conversation and encourage increased attention to childhood development among clinicians and caregivers.

“It is our hope that these conversations will result in discussion of concerns and appropriate next steps, including screening and further evaluation, when needed,” Hunter said.