Preferred sleep position and gross motor achievement in early infancy.

The aim of this study was to assess the effect of an infant's favoured position on their motor development at the age of six months. Seventy-five full-term infants were prospectively observed at home for their preferred sleep, awake, play and uninterrupted positions. A parental log was completed daily and then weekly up to the age of six months, when the Alberta Infant Motor Scale (AIMS) was administered. No significant relationship between the preferred or sleep positions as well as the awake and mutual play positions and gross motor developmental attainment at six months of age was noted. A significant change in the preferred recumbent posture with increased prone positioning both during sleep and awake time over the first six months was noted. A balanced positioning policy while awake, regardless of the infant's preference while recumbent, is not associated with gross motor delay.