A study conducted on 43 children suffering with breathing problem by researchers from the University of Auckland showed 90 percent of them had been left sleeping in the car seats unattended.

Professor Alistair Gunn of the University of Auckland in Auckland, New Zealand, said parents should not leave babies for 'excessive periods' in car seats.

"Infant car safety seats are vital to protect young infants from injury and death in motor vehicle accidents. However, infants with certain health conditions are at risk of oxygen de-saturation and apnoea - temporary suspension of breathing - while they are restrained in recommended semi-reclining infant car seats," Gunn said.