Association of Preterm Birth with Delayed Motor Development on Different Age Groups during the Second Year of Life.

Background: Studies indicate that preterm birth (PT) can be associated with delayed motor development during childhood. However, even if inconclusively, some studies have revealed that delayed motor development on PT are related to the investigated age group.

Aims: To analyze the association of PT with delay of fine and gross motor development in different age groups on the second year of life.

Method: 2006 children, belonging to a birth cohort initiated in 2010 and followed-up on their second year of life in 2011/2012, were analyzed. This follow-up sample included all cases of preterm birth (n=421) and approximately ¼ at term children (n=1585). The children were assigned to four age groups related to their age at examination: 13- to 16-month old (Group 1); 17- to 20-month old (Group 2); 21 to 22-month old (Group 3) e 23 to 24-month old (Group 4). The Bayley Scales III–screening was used to evaluate fine and gross motor development. The relative risk was calculated by means of Poisson regression models to verify the association between groups and motor delays for each group age. The models were adjusted for confounding variables identified by the directed acyclic graphic. Weights and stratifications were considered in the analyses.

Result: The PT group showed higher delay risks only in age groups 1 and 3, on fine motor skills (RR = 1.84, IC95% 1.23; 2.75 and RR = 2.69, IC95% 1.35; 5.35 respectively) and gross motor skills (RR = 2.72, IC95% 1.69; 4.39 and RR = 3.15, IC95% 1.64; 6.05 respectively) when compared with children born at term.

Conclusion: The PT children exhibit variability and time oscillation in attaining motor skills throughout the second year of life, being comparable to their counterparts at term by the end of this time.