Behaviour and development in 24-month-old moderately preterm toddlers.

Objective: Moderately preterm children (gestational age 32-36+6 weeks) are at risk of cognitive and behaviour problems at school age. The aim of this study was to investigate if these problems are already present at the age of 2 years.

Methods: Developmental outcome was assessed at 24-months (corrected age) with the Bayley-III-NL in 116 moderately preterm (M=34.66 ± 1.35 weeks gestation) and 99 term born children (M=39.45 ± 0.98 weeks gestation). Behaviour problems were assessed with the Child Behaviour Checklist.

Results: With age corrected for prematurity, moderately preterm children scored below term peers on Receptive Communication skills (11.05 ± 2.58 vs 12.02 ± 2.74, p=0.02). Without correcting age for prematurity, moderately preterm children scored below term born peers on Cognition (8.97 ± 2.11 vs 10.68 ± 2.35, p<0.001), Fine Motor (10.33 ± 2.15 vs 11.96 ± 2.15, p<0.001), Gross Motor (8.47 ± 2.55 vs 9.39±2.80, p=0.05), Receptive Communication (10.09 ± 2.48 vs 12.02 ± 2.74, p<0.001) and Expressive Communication (10.33 ± 2.43 vs 11.49 ± 2.51, p=0.005) skills. Compared with term peers, more moderately preterm children showed a (mild) delay (ie, scaled score <7) in gross motor skills with age uncorrected for prematurity (20.7% vs 11.2%, p=0.04). Moderately preterm children had more internalising behaviour problems than term children (44.76 ± 8.94 vs 41.54 ± 8.56, p=0.03). No group differences were found in percentages of (sub)clinical scores.

Conclusions: At the age of 2 years, uncorrected for prematurity, differences in cognition, communication, and motor development were present in moderately preterm children compared with term born peers. After correcting age for prematurity, a difference was only found for receptive communication skills. In addition, moderately preterm children show more internalising behaviour problems.