Odds of developmental delay in former preemies linked to timing of assessment

ByRose Weldon

Fact checked byCarol L. DiBerardino, MLA, ELS

Key takeaways:

Former extremely preterm infants assessed at an adjusted age of 21 to 24 months are more likely to be diagnosed with a developmental delay.
Odds are lower among infants assessed between 18 to 20 months.

Assessing formerly extremely preterm infants at a corrected age of 21 to 24 months is associated with higher odds of detecting a significant developmental delay than assessing them at an earlier time, a study published in Pediatrics found.

“Outcomes research on extremely preterm infants frequently examines neurodevelopment in the toddler years as a primary endpoint because of the higher chances of identifying developmental challenges,” the authors wrote. “The age range at which this occurs varies from one study to the other.”

Kids_Play — Assessments performed at 21 to 24 months’ corrected age were independently associated with a higher chance of detecting a significant developmental delay. *Image: Adobe Stock*

Development in toddlers changes from one month to the next, they wrote — changes that are measured using the Bayley Scales of Infant and Toddler Development, which accounts for developmental changes using play tasks to evaluate language and cognitive and motor skills, which more complex with increasing age.

According to the authors, one concern in studies allowing for a larger age range during assessment is that children seen at a later age “may be at a disadvantage” compared with those seen earlier in their lives because of “higher developmental expectations that can unmask challenges not previously observed.”

“Conversely, preterm children with latent developmental problems who are assessed too early may be missed,” they wrote. “Therefore, the timing of assessment may influence identification of developmental delays, which are important at the individual child level to direct early intervention and at the macro-level for establishing time trends in outcomes and benchmarking between units.”

For their study, the researchers pulled data on 3,944 children born before 19 weeks’ gestation who were admitted to sites in the Canadian Neonatal Network between 2009 and 2017, and compared groups of children assessed at 18 to 20 months’ corrected age with children assessed at 21 to 24 months’ corrected age.

The primary outcomes were significant developmental delay — a Bayley-III score below 70 in any domain — and developmental delay, which was a Bayley-III score above 85 in any domain.

Compared with the infants assessed at 18 to 20 months, those assessed at 21 to 24 months had higher odds of significant developmental delay, 20% vs. 12.5% (adjusted OR = 1.75; 95% CI, 1.41-2.13), and developmental delays, 48.9% vs. 41.7% (aOR = 1.33; 95% CI, 1.11-1.52). Bayley-III composite scores were on average three to four points lower in infants evaluated at 21 to 24 months’ corrected age.

“We speculate that later age of assessment unmasks developmental challenges as the complexity of the tasks increase,” the authors wrote. “Our findings have relevance to neonatal follow-up clinics that rely on the Bayley to identify children with significant developmental delay to trigger referrals for early intervention, observational studies exploring the association between neonatal exposures and 18- to 24-month Bayley-III assessments, and network benchmarking.”

In a perspective, Joseph G. Barile, BA; Kyle Han, BA; and Ruth Milanaik, DO, all of Cohen Children’s Medical Center, wrote that the consequences of prematurity vary greatly and, “so do the supportive needs of former preterm children.”

“Considerations of corrected age on kindergarten entry will not always be relevant; some preterm children will be more than prepared for kindergarten, whereas others will already have obvious developmental issues that kindergarten delay will not rectify,” they wrote.

For certain cohorts of former preterm children, like children born early-preterm, the use of corrected age “can elucidate why entering kindergarten may be inadvisable,” they said.

“In these instances, pediatricians can attest that an additional year of development will be beneficial and subsequently, recommend to school districts that the child’s kindergarten year is delayed while pre-K services are extended,” they wrote.