New research warns that babies should never be allowed to sleep in car safety seats when the seat is not in a car because it can cause decreased oxygen levels.

Babies’ heads are larger, relative to the body, than adults’ heads, and protrude behind the line of the back. Commercially available simple foam inserts with a slot for the back of the head help keep the baby’s body forward. They also allow the head to remain upright even when the infant is asleep, rather than slumping forward, which can obstruct breathing when the chin is on the chest and pushed back. The study, published inPediatrics, confirms that using the insert does reduce breathing risks for babies who were on average 8 days old, but it does not eliminate the seats’ risks.

Researchers note car safety seats are essential for infants’ safe transport in cars but they express concern at the reported high rates of infants spending more than 30 minutes a day in a car seat, “often for sleep out of the car as well as for transport.” Even when the insert is used, young infants should never be left unattended in car safety seats. “Car seat use should be restricted to the minimum time required for essential travel.”

Researchers emphasize “there is now compelling evidence that hypoxia

[oxygen deficiency] is associated with behavioral problems and adverse effects on development and school performance.”

Read more on this study.

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