BOSTON (CBS) — Every year, several hundred babies die in sitting devices like car seats and strollers. A new study in the journal Pediatrics found many of those deaths occur when babies are left to sleep in car seats unsupervised, outside of the car.

Researchers studied almost 12,000 infant sleep-related deaths and they found about 3 percent occurred in sitting devices.  Almost two-thirds of those in car seats, about one-third in bouncers and swings, and 2 percent in strollers.

READ MORE: Watch Live @ 9 am: Baker Visits Newburyport School's Pool COVID-19 Testing Program

More than half of the deaths in sitting devices occurred in the child’s home and were more likely to occur while the baby was being cared for by a child care provider or babysitter rather than a parent.

READ MORE: 582 At Massachusetts Schools Test Positive For COVID-19 In Last 2 Weeks

Pediatricians said don’t worry if your baby falls asleep in a car seat while traveling in a car. That’s the safest place for them to be.

MORE NEWS: Friday Marks First Anniversary Of Boston Biogen Conference Super Spreader Event

But they reminded parents that car seats and strollers were intended to be used for travel and not for the stationary restraint of children.  So when no longer traveling, the best to transfer your sleeping baby to a crib or a bassinet.

Dr. Mallika Marshall