Toddlers who spend time playing on smartphones and tablets seem to get slightly less sleep than those who do not, say researchers.

Axar.az reports that the study in Scientific Reports suggests every hour spent using a touchscreen each day was linked to 15 minutes less sleep. However, those playing with touchscreens do develop their fine motor skills more quickly.

Experts said the study was "timely" but parents should not lose sleep over it. There has been an explosion in touchscreens in the home, but understanding their impact on early childhood development has been lacking.

The study by Birkbeck, University of London, questioned 715 parents of children under three years old. It asked how often their child played with a smartphone or tablet and about the child's sleep patterns.

It showed that 75% of the toddlers used a touchscreen on a daily basis, with 51% of those between six and 11 months using one, and 92% of those between 25 and 36 months doing so as well. But children who did play with touchscreens slept less at night and more in the day.

Overall they had around 15 minutes less sleep for every hour of touchscreen use.