Infants Need Daily "Tummy Time" for Early Motor Development

Infants Need Daily "Tummy Time" for Early Motor Development

Supine sleepers were more likely than prone sleepers to have motor delays.

Placing infants in the supine position during sleep has been associated with a dramatic decline in the incidence of sudden infant death syndrome. However, small studies based on parental reports or global screening tools have reported that supine sleep positioning might be associated with delays in gross motor milestones, perhaps because these infants also spend more awake time on their backs. Prone positioning is necessary for infants to learn motor skills that require antigravity extension (e.g., prone rolling and sitting).

Investigators in Canada compared motor skills in healthy white infants at either 4 months (71 supine and 12 prone sleepers) or 6 months (50 supine and 22 prone sleepers) of age. Two standardized tests were used to evaluate infant motor function, and parents recorded infant positioning while awake. All infants were reassessed at 15 months.

At 4 months, infants in the supine group had lower motor scores and were significantly less likely than prone sleepers to achieve prone extension on their arms. At 6 months, differences in motor development between the supine and prone infants increased significantly; 22% of infants sleeping in the supine position had gross motor delays and also were less likely than prone sleepers to sit and roll. Among supine sleepers, more time spent in the prone position while awake was positively correlated with better motor performance. At 15 months, baseline sleep position still predicted motor performance.

Comment: The environment matters! This study provides the first empirical evidence that "back-to-sleep" supine positioning of infants slows gross motor development. Although infants who sleep in the supine position might be more reluctant to spend time in the prone position during the day, daily exposure to "tummy time" improved motor skills. Pediatricians should be aware of this environmental effect on motor development, encourage prone positioning during awake hours, and avoid unnecessary referrals when motor delays occur secondary to positioning. In the future, normative scales for early motor development might take into account the effect of infant positioning when awake and asleep.

— Martin T. Stein, MD

Published in Journal Watch Pediatrics and Adolescent Medicine January 31, 2007