Advances in Neonatology and Pediatric Psychiatry

Studies have established that school-age children who are born preterm and with very low birthweight will generally present with more cognitive deficits and behavior difficulties – withdrawn, anxious/depressed, and attention deficits – than children born at term. But are these concerns also typical of toddlers? Research has not focused on the relationship of preterm birth to cognition and behavior problems in children 18 months to 3 years old.

This being the case, neonatologist Jeffrey M. Perlman, MB, ChB, and child and adolescent psychologist Gail S. Ross, PhD, at NewYork-Presbyterian Komansky Children’s Hospital, came together to examine if similar consequences surface in this younger age group and whether they continue to develop over time into the preschool years. Dr. Perlman is also Professor of Pediatrics and Dr. Ross is Clinical Associate Professor of Psychology in Pediatrics at Weill Cornell Medicine.

In their study, Dr. Perlman and Dr. Ross reviewed the charts of 124 very low birthweight preterm infants <1250g and <32 weeks at birth between 2010 and 2015 who were enrolled in the hospital’s Neonatal Neurodevelopmental Follow-Up Clinic for 18-month and 36-month evaluations. At each visit, parents were asked to complete the Child Behavior Checklist to rate behavior problems. At the 18-month visit, the Cognitive Scale of the Bayley Scales of Infant and Toddler Development was completed. At the 36-month visit, the Wechsler Preschool and Primary Scale was administered and pediatricians evaluated the children for autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). Socioeconomic status (SES) and sex, factors known to affect the prevalence of behavior problems and cognitive scores in preterm children, as well as diagnoses of ASD and ADHD, were also included in the analysis.

“To our knowledge, previous studies have not examined the trajectory of the relationship of behavior problems and cognition between the toddler and preschool period to determine when and if such relationships develop over time during this age range.” — Dr. Jeffrey Perlman and Dr. Gail Ross

The findings, published in the February 2022 issue of Infant Behavior and Development, showed:

• Analogous to other studies, lower SES was significantly associated with higher behavior problem scores, particularly for withdrawn behaviors and attention problems, at both 18 months and 36 months.
• For anxiety/depressed behavior problem scores, children in the upper SES group had significantly lower scores than those in the middle SES group at 36 months. However, the authors note that the influence of parent perceptions, expectations, and ability to manage behavior problems may contribute to their scoring.
• Sex did not factor significantly into differences in behavior problems, findings that were also consistent with some other studies.
• Withdrawn behaviors at 18 months and 36 months were significantly related to 18- month and 36-month cognitive scores, while anxious/depressed and attention problems were not.
• Withdrawn behavior problems at 18 months were significantly associated with 36-month cognitive scores, indicating that higher withdrawn behaviors predicted lower cognitive scores at 36 months. However, a significant relationship was not found between 18-month anxious/depressed and attention problems scores and 36-month cognitive scores.
• The attention problems difference score was significantly related to the cognitive difference score, showing that increase in attention problem score was associated with decrease in cognitive score. Conversely, withdrawn and anxious/depressed behavior problem difference scores were not significantly associated with the cognitive difference score.
• Diagnoses of behavior problems made by pediatricians were significantly related to parents’ behavior ratings when children were 36 months old. A diagnosis of ASD was significantly associated with parents’ ratings of withdrawn behaviors and, similarly, a diagnosis of ADHD was associated with higher scores on attention problems at 36 months.
• Lower SES was significantly related to lower cognitive scores at 36 months but not at 18 months of age, indicating that SES has an increasing effect on cognitive scores as children mature from the toddler to preschooler period, when more complex conceptual and language abilities are assessed.

With these findings in mind, and, in particular, the continuity between withdrawn problem scores with lower cognitive performance from 18 months to 36 months, Dr. Perlman and Dr. Ross emphasize that toddlers and preschool children born preterm at very low birthweight should be closely monitored during this period of development. Ongoing follow-up provides a window of opportunity in which to evaluate and address behavior problems and cognitive delays before children begin their preschool years.