The cause of the hypoxia while placed in the car safety seat is most likely attributable to the relative vulnerability of the airway in the premature and term infant. The cause of the airway narrowing is slouching of the head forward while asleep in car seats which results in closure of the mouth, the pressing of the tongue against the posterior pharyngeal wall and the flexion of the airway. The shape of the newborn head with a prominent occiput and the reduced muscle tone encourages head slouching. A recent pilot study suggested that the placement of an insert which accommodated the occiput thus reducing the tendency towards flexion improved airway size and reduced the frequency of episodes of oxygen desaturation. Thus the flexion position, which is unique to the car seat, may have important implications for the airway of the newborn.