Motor development from 4 to 8 months corrected age in infants born at or less than 29 weeks' gestation

Aim: Clinically, preterm infants show motor delay and atypical postures compared with their peers born at term. A longitudinal cohort study was designed to describe the motor development of very preterm infants from 4 to 18 months corrected age (CA). The study was also designed to investigate how the atypical postures observed in early infancy in the preterm infants might be related to their later motor development. Here we report the findings in early motor skills from 4 to 8 months CA. Method: Early motor skills were assessed in 62 preterm infants (32 males, 30 females, mean gestation 26.94wks, SD 1.11) and 53 term infants (32 males, 21 females, mean gestation 39.55wks, SD 1.17) using the Alberta Infant Motor Scale (AIMS). Results: The preterm infants demonstrated different motor behaviours from their term peers, with an uneven progression of motor skills in different positions from 4 to 8 months CA. At 8 months CA, 90% of the term infants were able to sit without arm support, but only 56% of the preterm infants could maintain sitting very briefly without arm support. Interpretation: This uneven progression may have been due to an imbalance between the active flexor and extensor strength and hence inadequate postural control in these positions. The AIMS has also been shown to be a valid assessment tool to demonstrate unique characteristics in movement quality in the preterm population.