Collaborative ECHO research led by Michael O’Shea, MD, MPH of the University of North Carolina, Chapel Hill, School of Medicine investigates the effects of growth and weight gain during infancy on neurodevelopment and obesity in children born very preterm. This research, titled “Association of Growth During Infancy with Neurodevelopment and Obesity in Children Born Very Preterm: The Environmental influences on Child Health Outcomes Cohort,” is published in the Journal of Pediatrics.
Infants born preterm typically have a period of poor growth in their first few months. After this stretch, they typically exhibit “catch-up” growth defined by an increase in weight z-score—a measure to classify a child’s nutritional status—during childhood and adolescence.
Prior research suggested that a “trade-off” may be associated with catch-up growth, such that individuals with more rapid weight gain during infancy have better neurodevelopmental outcomes than individuals with less weight gain. However, rapid catch-up growth during infancy has also been associated with a higher risk of becoming overweight or obese.
This study involved 1,400 children born before 32 weeks of gestation in hospitals in multiple states in the U.S. between 2002 and 2020. A majority of these children experienced neonatal complications—issues faced during the first 28 days of life—the most common of which was neonatal chronic lung disease. These children were followed for 1 to 4 years, at which point their BMI and neurodevelopmental outcomes were assessed. The data collected allowed for analyses of relationships between weight gain following NICU discharge and neurodevelopmental outcomes and BMI at 1 to 4 years of age.
The study team found that in comparison to infants with low weight gain after birth, infants with very high weight gain after NICU discharge, experienced by 13.6% of participants, had higher body mass index (BMI) scores and a higher risk of obesity at 12-48 months.
The study team also found no evidence that very high weight gain after NICU discharge was associated with better neurodevelopmental outcomes at 12 to 48 months of age. However, infants with very low weight gain after NICU discharge had lower scores on cognitive and language assessments. No significant differences were found between girls and boys.
These results suggest there are possible benefits of close monitoring of post-NICU growth and healthier feeding practices to prevent obesity, which is associated with multiple adverse health outcomes.
“Because this study suggests that very preterm infants who experienced a very high increase in body weight during the first four years after NICU discharge were more likely to have a high BMI with similar neurodevelopmental outcomes, avoiding high weight gain might be beneficial to very preterm infants’ health,” Dr. O’Shea said. “However, as single studies rarely provide sufficient evidence to change clinical practice, this study should not be the sole basis for such changes. If the findings of this ECHO study are replicated in other studies, changes in clinical practice might then be appropriate.”
Future studies are needed to evaluate the relationship between the pace of weight gain during early childhood, long-term developmental outcomes, and changes in children’s BMI. This study focused on weight gain among infants born very preterm after discharge from the NICU. Additional studies are needed to observe the effects of different rates of catch-up growth on infants born closer to term.