Motor trajectories of preterm and full-term infants in the first year of life.

Background: Motor development occurs throughout periods of motor skill acquisition, adjustment and variability. The objectives of this study were to analyze and compare biological and health characteristics and motor skill acquisition trajectories in preterm and full-term infants during the first year of life.

Methods: Two thousand, five hundred and seventy-nine infants (1,361 preterm) from 22 states were assessed using the Alberta Infant Motor Scale. Multivariate General Linear Model, t-tests, ANOVA, and Tukey tests were used.

Results: An age × group significant interaction was found for motor scores. On follow-up tests full-term infants had higher scores in prone, supine, sitting and standing postures that require trunk control from 9 to 10 months of age; although this advantage was observed for sitting from the second month of life.

Conclusion: During the first trimester of life, preterm infants have higher scores in the supine and standing postures. Regarding motor trajectories, from newborn to 12 months, the period of higher motor acquisition was similar between full-term and preterm infants for prone (3-10 months), supine (1-6 months), and standing (6-12 months). For the sitting posture, however, full-term infants had a period of intensive motor learning of acquisition from the first to 7 months of life, whereas for preterm infants a shorter period was observed (3-7 months).

Conclusion: Although the periods of higher motor acquisition were similar, full-term infants had higher scores in more control-demanding postures. Intervention for preterm infants needs to extend beyond the first months of life, and include guidance to parents to promote motor development strategies to achieve control in the higher postures.