Predictors of motor developmental milestones during the first year of life.

Several individual factors, especially gestational age, birth weight, breastfeeding, having lived in a full-time institution, and weight and head increase in the first year, were significantly associated with milestone attainment in the first year of life. Variables within the domain of Pregnancy and delivery explained the largest proportion of variance in milestone attainment compared to the other domains. What is known: • Younger age at attainment of motor developmental milestones positively predicts cognitive outcomes in adulthood. • Both pre- and postnatal factors have been associated with age of attaining milestones in infancy. What is new: • First study to provide a systematic evaluation of a broad selection of predictors of infant milestone attainment. • Variables within the domain of Pregnancy and delivery, especially gestational age and birth weight, explained the largest proportion of variance in milestone attainment. • The variance explained by the predictors decreased time-dependently with later milestones.