Purpose: To compare motor and cognitive performance in infants with typical development in the 1st, 2nd, 3rd, 6th, 9th, and 12th months after birth.
Methods: This was a repeated-measures study with unequal sample sizes in the follow-up periods, comprising 94 infants born at term. Infants with genetic syndromes, malformations, congenital infections, or hospitalized in intensive care units were excluded. The Bayley Scales of Infant Development II were used for evaluation of cognitive and motor performance.
Results: There were significant differences between motor and cognitive performance at 1, 2, and 3 months. However, at 6, 9, and 12 months, there was no difference between domains.
Conclusion: This study suggests that during the first year, development can be synchronous in the 2 areas evaluated by the Bayley Scales of Infant Development II, especially from the sixth month of age onward.