A new study finds the position of some infant car seats can compress a baby's chest wall and reduce their airway .
Moreover, not breathing effectively can lead to low oxygen levels.
Lower oxygen levels in older children have been linked to learning and behavior problems.
The study looked at 200 newborns.
Infants left in a crib had much higher levels of oxygen than those babies who were left in car seats or car beds, for more than one hour.
Researchers best advice is that children should only be in a car seat when they're in the car.
Don't use the seat as a crib.
"If the baby falls asleep in the car seat while your out and you are now home, it is important to, as gently as you can take the baby out of the car seat and place the baby in the crib," said Dr. Deborah Campbell, Director of Neo-Natology at The Children's Hospital at Montefiore, Calif.
Click here for a guide on how to properly install car seats and booster seats
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